AC on? Might be dirty plugs or injectors.

What do you know of the maintenance that has been performed?

MAF sensor could be dirty, or the air tube not sealed correctly after changing the filter.

BTW, do you plan to comment any further in THIS thread, or will this be just another "one and done" like your other thread from August 2015?

 

BTW, do you plan to comment any further in THIS thread, or will this be just another "one and done" like your other thread from August 2015?

Nice observation! Change your attitude, or this will be a “two and done”.

 

If it shakes in drive but not in N or P mounts may be worth a check too.

I don't think DD meant any insult just a nudge. Your previous thread has others offering help but you never bothered to respond, thank, or offer a conclusion. Threads are useless if they go that route.

Best of luck!

 

Thought I’d look at the mounts, just seems uncommon for 115k miles. I’ll check those out tomorrow. Thank you sir!

 

campb292 is right, DD wasn't necessarily being mean but it's true, if you come back and let us know what worked for you, we can have a bit of closure knowing that we helped offer the right fix for you and it can help others having the same issue as well.

Did you check your RPMs when you're idling in drive? Does it seem to dip a bit more than normal or does it stay in the normal idle range? It sounds like it's struggling a bit to stay going. I would definitely check the spark plugs. I would also keep an eye on your fuel consumption to see if you're running rich or lean. Either condition is bad but you should have a light on for that if it's severe enough. Is the engine itself shaking? You might want to check this thread out. It might not necessarily offer a solution but it's also possible you could have a little bit of corrosion that's not exactly enough to trigger the all to common engine power reduced, but might be heading that route: http://www.chevymalibuforum.com/for...shooting-generation-7/8240-fretting-corrosion-service-traction-control-ecs.html

As DD also said, check your A/C and see if it happens with or without it. How is your power taking off? Does it seem like it gets enough fuel to race through the RPMs at full throttle? Try full throttle and see if it hiccups or not. If it does, I'd suspect something with the fuel delivery or too much air getting into the system. Just weird that it wouldn't trigger a light though. Does the check engine light actually work? It'll be right on the bottom of your temperature/fuel gauge and you'll see it if you turn the ignition to on but don't start it. I'm sure it does but it's always good to double check!

 

I stand with ya DD.
I'm not an Admin. so I can speak freely . Flying in for freebie advice previously without any response and having the balls to do it again AND be a smart ass means ''no soup for you''.
BTW I know what's wrong with ya car....

 

Now the RPMs on the tach stay put, gonna see if this tune up helps any. Thanks for the advice guys, will see if these help the issue. Car was from the north, so it has seen a lot of salt and I see some surface rust.

 

Hoping you DO know what is wrong with it! My 2013 Malibu started shaking like it was on a rubber band today when in drive and stopped. I drove one block. The RPMs stay at 500 mark in park and in drive. Only in drive while braked does it shake terribly. I can also hear a knocking. The Reduced Engine Power warning comes on after being turned on for more than 30 seconds. The O2 sensors were replaced and the spark plugs last month. I keep seeing major issues on forums with Malibu s and after replacing the throttle body amongst other sensors and the drains from the sunroof it seems these issues are recurring with no solutions in forums over and over and over. Hoping you have more info. Im thinking its probably trashed.

 

I had this problem in with my previous 2011 Malibu LTZ 2.4L 110,000 km.

After I turned on the car, if the front dehumidifier is on, the car will noticeably shake/vibrate. You can easily feel it in the steering wheel, foot pedal, headrest and even the seat. This is most noticeable from a cold start, after which, it's harder to recreate the intensity of the issue.
But yes, put it in neutral and there is no shake.

According to the dealer, it's the higher RPM at idle that causes this when there is more strain on the engine from the a/c, dehumidifer, etc.

This was bother me so much, that I scoured online to find anything that would be a solution and the best alternative was to replace the engine mounts. Let me save you some time and money, as I replaced all engine mounts, there was no change. And I lost $700, after multiple trips to the dealer and several calls to the Canadian head office.

I traded my car for a 2012 Malibu LTZ V6 and it's less noticeable, however, I can still feel the strain on the engine. That being said, my it's not as annoying lol.

I hope this helps, maybe not the answer you're looking for... :/

 

I had this problem in with my previous 2011 Malibu LTZ 2.4L 110,000 km.

After I turned on the car, if the front dehumidifier is on, the car will noticeably shake/vibrate. You can easily feel it in the steering wheel, foot pedal, headrest and even the seat. This is most noticeable from a cold start, after which, it's harder to recreate the intensity of the issue.
But yes, put it in neutral and there is no shake.

According to the dealer, it's the higher RPM at idle that causes this when there is more strain on the engine from the a/c, dehumidifer, etc.

This was bother me so much, that I scoured online to find anything that would be a solution and the best alternative was to replace the engine mounts. Let me save you some time and money, as I replaced all engine mounts, there was no change. And I lost $700, after multiple trips to the dealer and several calls to the Canadian head office.

I traded my car for a 2012 Malibu LTZ V6 and it's less noticeable, however, I can still feel the strain on the engine. That being said, my it's not as annoying lol.

I hope this helps, maybe not the answer you're looking for... :/

Putting it in neutral removes some of the load on the engine that otherwise slows it down. On a cold start, the computer enriches the A/F ratio and raises the idle some. During a cold start is when it should shake less, not more, since the RPMs are higher than after it has warmed up.

The dealer saying that the A/C (which is the dehumidifier) puts more strain on the engine is correct, but the "higher RPM at idle" seems to maybe be a misquote. At idle the engine is at its lowest RPM, and any load placed on it, such as A/C or putting it in gear or exercising the steering wheel, will make it work harder. When that happens at the lower RPMs during idle, it will have a harder time recovering from the load and may be not as smooth as normal. Easiest cure is to give it a little gas yourself and see if that makes it feel better to you.

The three 3.6L V6 engines that I've had the pleasure of owning have not had any rough idle after cold or warm starts, with or without the A/C.

 

I agree Brad, the 4-bangers are just unbalanced compared to the V6. The 3.6 is much smoother.

 

I am sorry for commenting on an older post, but I am now having the same problem with our 2012 Malibu 1LT after replacing a broken exhaust flex pipe. I'm suspecting the flex pipe may have broken because of loose mounts and the problems are related. The issue definitely wasn't there until after I replaced the exhaust component. Did this problem ever get resolved?

I am going to give the car a thorough diagnosis 8/20/2019 and see what I find, but I'd really like to know if anyone solved this first.

 

Update:

The car is about to hit 80,000 miles, so it was due for some service anyway, in addition to another exhaust leak.

The flange on the inlet of the catalytic converter/ downpipe assembly that bolts to the manifold flange came loose, and was leaking. I had that welded and now everything is quiet again.

I drained and filled the transmission. 5 quarts out, 5 quarts in.

The original spark plugs were replaced with Auto Lites. They are iridium and gapped to .043 like the OE plugs. I couldn't find OE Delco plugs in time.

I cleaned the MAF and throttle body with appropriate solvents.

The engine still shakes violently while stopped and in drive. Having the A/C on makes it worse. The problem goes away with some throttle or once you get going above 3 or 4 mph or so. It doesn't shake in park, neutral, or reverse. Curiously, it also doesn't shake if you come to a stop locked in 2nd gear. If you then shift to 1st, it shakes. If you're already stopped in 1st and shift to 2nd, the shaking does not go away. (This car allows for idling and starts in 2nd gear for more control and less torque in slippery conditions) I have NO obvious driveability, performance, or transmission issues. No stumbling or hesitating, the transmission shifts fine. I have no clues to focus in on.

• Whatever the problem is, it acts like its in the transmission. I have had to wind this engine up in drive with the brakes applied to diagnose exhaust leaks and timing chain noises, but never anything irresponsible or stupid. Just to 2,000 rpm or so to replicate noises and leaks under load. It's possible I've collapsed an engine mount or caused something in the drive line some harm, but I tend to doubt that. This car is so low mileage and it has been maintained to the tee since new by me. I do all my own work and notice things pretty quickly.

My next steps are to check the fuel system- mainly injectors, and make sure they are clean and working right. If they check out, it's going in for a transmission diagnosis at an independent shop. I do not trust any of my local GM dealers. They are all terrible.

I am determined to solve this problem myself, or find someone who can and report back.

 

In an earlier post you mention that it's a 2012 1LT. I assume that that also means that it's the 2.4L 4-cylinder.

Do you have a yellow gas cap, indicating that it's capable of consuming E85?



Quick questions that might not apply, but then again they might.

Do you use Top Tier fuel?

Do you use the recommended octane and maybe bump it to the next one up when it's really warm and muggy out?



I see that you're going to check the fuel system. Shaking only in 1st gear suggests to me that there's an issue in the transmission, just like you mentioned. I hope not . . .

 

Correct.

2.4L 6T40 (2nd gen), not a flex fuel car.

This car has never been picky about fuel. It doesn't ever ping or detonate, and like I said, there are no driveability issues. I dont think this is a fuel quality issue. The engine and trans both feel as good as they ever have, just this shaking is the only symptom.

I'm going to check the fuel system just because I haven't yet, but the more I dig into this problem, the more I think trans and not engine.

I just read thisTSB for the 6T40.

https://www.google.com/url?sa=t&sou...UkwFkKHYN6AP4QFjACegQIAxAB&usg=AOvVaw1jNj2sE5-eAHHVRWu1NRSN&cshid=1567046962541

[/URL]

Basically it describes the exact condition described in this thread. But, as I've already stated, shifting into "M" while idling and selecting gears manually doesnt alleviate the problem. Another drive tonight and now even stopping the car while locked in 2nd doesn't help. I will look at my scan tool data and see what the trans temp sensor is doing. It's worth noting that the problem existed before I changed the fluid and the problem is unchanged.

I hate this car. It has been nothing but problems. I had to do a timing overhaul at 60,000 miles because one of the guides snapped. The exhaust manifold cracked, a wheel bearing failed, this latest exhaust problem, various interior switches have failed, it just never ends. If I can't solve this, I will sell it, but I'm determined, because this is a low mileage car that I have a full service history on.

 

I realize that link doesn't work. Here it is as a PDF.

 

That bulletin won't be relevant since you note the shake continues in M, plus that bulletin is for cars equipped with the 1.4L and 6T40 and specific models. Another reason bulletins are for professionals, not those that do not understand the components of a car or how to read a bulletin. Have the motor and transmission mounts been inspected? I am curious as you said this problem only started after replacing a broken exhaust flex pipe. Perhaps excessive movement of the powertrain caused stress to break the part.

 

That bulletin also denotes 6T40 equipped cars built before 2013. Ours fits that. You're right, the symptoms don't match up exactly, but close enough that it was worth noting.

I think the exhaust thing is just a coincidence. My parents' 2004 Malibu went through several exhaust flex joints, and never had this shaking issue. It also had the 4T40 which was a vastly better transmission. That car came to us for free and left us with 250,000 miles on the original trans fluid. It ran great. Just the body and suspension rotted out from under it. Our car had been leaking at the flex for quite some time before I got around to replacing it. The shaking problem showed up right after I replaced the flex joint, but I don't see how the new flex joint could be the cause. I think the trans took a dump as I was loading the car up in drive to check that the leak was gone. Again, that's something you should be able to do without causing transmission problems. Starting on a steep grade puts way more slip and strain on an automatic trans than brake-standing at 2000 rpm for a few seconds at a time.

I might be willing to replace engine mounts, but the engine doesn't shake in reverse. In my experience, bad engine mounts mean a shaky idle no matter what position the shifter is in, and shakes when accelerating. There is no shake whatsoever until it's put in a forward gear while sitting still, and then it disappears completely when you're rolling. This is definitely a transmission issue. I'm going to have a shop diagnose it most likely. I will not authorize them to just throw parts at it. This car has just had its 80,000 mile baseline anyway. It runs flawlessly in every other aspect. If they can't pinpoint exactly what's wrong to my satisfaction, the car will stay this way until we can get rid of it, which after all it's cost us on repairs we've been considering anyway.

 

@1DI0CRACY can you get a video of the car (hood open) idling in neutral and then have someone put it in drive with the brakes applied to illustrate the shaking? I want to show it to my dad this weekend, he is a retired GM master technician and is completely familiar with the gen 7 Malibu as well as all Chevy cars of the time.

 

I'd be happy to. I'll get that done today.

 

Update! I feel like a complete idiot. The flex joint is most likely related if not the cause of all this.

I didn't notice until I went to try and capture a video of the engine vibrating. I was using a glass of water held on top of the idiot cover and shifting between drive and neutral with my hand on the end of the shifter cable. The change in vibration in the engine and transmission is very minimal.

What is NOT minimal, is the change in the exhaust. It is dancing around like crazy under there, but only in drive, which explains why I can feel it more in the seats than anything else. It's coming from right under the floor. There's just something about the angle at which the engine sits while in forward gears at idle that allows the exhaust to shake/ resonate up and down really bad. I'm talking total deflection of an inch or more at the secondary catalyst right after the flex joint.

For whatever reason, this flex joint is allowing a ton more movement than the leaky OE flex joint. I am going to put my broken flex joint back in to test this theory.

I'll report back probably this weekend.

 

Was there an anchor for the exhaust that wasn't reattached after the exhaust work?

 

I thought about that right after my last update. To answer your question, no, but they could be worn out or broken and I didn't even notice.

There are only 5 rubber hangers/ isolators in the entire system. I didn't have to disconnect any of them to do flex joint or downpipe work. There are two big isolators on the resonator between the rear passenger foot wells, and three of the biscuit style isolators on the muffler. They are cheap, and its been 7 years. It might be time for new ones.

I'm confident now I can fix this. All I have to do is tighten up the exhaust system so it doesn't have a resonant frequency that perfectly matches the vibrations of the engine at idle.

I'll look more closely at those rubber isolators this evening.

 

Pictures if you can manage them, please!

 

Hope everyone had a pleasant holiday weekend.

I put the car up on ramps this evening.

The exhaust isolators are fine. No rips, no sagging, not the slightest bit of cracking or dry rot.

That leaves one last possible part...

The flex joint simply allows too much movement right where it connects to the catalyst. I've tried making sure the flanges are aligned as best they can be, I've readjusted it a couple times, and I know I'm on the right track because the vibration changes every time I adjust the flex pipe, but it's still there. When the angle changes as the engine moves in the mounts, which is a totally reasonable amount, it slowly builds a crazy amount of vibration. The harmonic builds until you can feel it in your body and eardrums but goes away as soon as you touch the go pedal.

The OEM flex pipe is almost $200. I'm really not looking to pay a ridiculous dealer markup for a part that isn't guaranteed to solve the problem.

I think this is one for an exhaust specialist. Luckily all the exhaust damage this shaking has caused means I know a good one. If they have to weld in an additional exhaust hanger at the outlet of the flex pipe to solve this, so be it. If I don't address it, exhaust parts will keep breaking. I'll keep you posted.

 

Hope everyone had a pleasant holiday weekend.

I put the car up on ramps this evening.

View attachment 67475

The exhaust isolators are fine. No rips, no sagging, not the slightest bit of cracking or dry rot.

That leaves one last possible part...

View attachment 67476

The flex joint simply allows too much movement right where it connects to the catalyst. I've tried making sure the flanges are aligned as best they can be, I've readjusted it a couple times, and I know I'm on the right track because the vibration changes every time I adjust the flex pipe, but it's still there. When the angle changes as the engine moves in the mounts, which is a totally reasonable amount, it slowly builds a crazy amount of vibration. The harmonic builds until you can feel it in your body and eardrums but goes away as soon as you touch the go pedal.

The OEM flex pipe is almost $200. I'm really not looking to pay a ridiculous dealer markup for a part that isn't guaranteed to solve the problem.

I think this is one for an exhaust specialist. Luckily all the exhaust damage this shaking has caused means I know a good one. If they have to weld in an additional exhaust hanger at the outlet of the flex pipe to solve this, so be it. If I don't address it, exhaust parts will keep breaking. I'll keep you posted.

Were you able to find the solution for the vibrating at idle? Or anyone else found the solution.. im having same issue, i alrrady replaced all engine mounts,spark plugs, clean throttle body and still vibrates at idle in Drive.☹

 

Check Rock Auto, they may have a no weld repair kit. They had one for my old Sable.

 

You used a cheap aftermarket flex pipe replacement?

Given that everything else is perfectly fine (anchors and whatnot), I think you're staring the problem in the face and desperately don't want to come to the conclusion that you wasted time and money on a bad flex pipe and a ton of troubleshooting.

Did the car shake before the flex pipe? If yes, keep looking. If no, buy an OEM flex pipe and be done with it.

 

UGH. I had this problem twice. GM model vehicles too. Your exhaust system is fine I bet on it, you would more than likely hear the vibration vs feel it first if it were the exhaust. One time it turned out to be a burnt valve. The other time the spark plugs. a miss, even a slight one could cause the transmission to exhibit certain symptoms as well making you think the problem is elsewhere. You may not be in the territory of a CEL just yet, but those autolite plugs, GET EM GONE. Even some Bosch are finicky, but I would try to find a scanner and monitor each cylinder or even scope into each one. Even do a coil check. 80k isn't a lot, but I have seen them go out at 10k even just intermit. That is if you already checked your mounts out already too, but you would see the flex mostly when doing the brake test.