[dallam1]

Gents; Working on my boy's 2005 Classic with the ecotec 2.2 engine with 140K miles. Changed the plugs oil and filter and did a transmission flush. Been an awesomely dependable auto for several years. The car is smooth and quiet but there's one annoying issue and that is a rough idle. Anything other than idle the engine is velvet smooth. It sounds like an egg beater at idle but wont stall nor hesitate on acceleration. I can feel the vibration when I put my hand on the valve cover at idle. The motor mounts seem ok...can't rock the engine....but with a vibrating engine not sure new mounts would smooth things out anyway. I don't want to throw parts at the car so I'm hoping one of u gents can lead me in the right direction. Hope all is well with all of you and thanks for any help.

 

[UmmScott]

Gents; Working on my boy's 2005 Classic with the ecotec 2.2 engine with 140K miles. Changed the plugs oil and filter and did a transmission flush. Been an awesomely dependable auto for several years. The car is smooth and quiet but there's one annoying issue and that is a rough idle. Anything other than idle the engine is velvet smooth. It sounds like an egg beater at idle but wont stall nor hesitate on acceleration. I can feel the vibration when I put my hand on the valve cover at idle. The motor mounts seem ok...can't rock the engine....but with a vibrating engine not sure new mounts would smooth things out anyway. I don't want to throw parts at the car so I'm hoping one of u gents can lead me in the right direction. Hope all is well with all of you and thanks for any help.

1st. Definitely check the motor mounts.

2nd... its a 4 cylinder and its a GM 4 cylinder. 4 cylinders are naturally out of balance more so than other engines and vibrate a lot more.

I would for sure check the motor mounts tho. Does it do it when its in park? Does it only do it when its in drive?
Also when looking at the motor mounts, small little cracks in the rubber are ok. What you need to look for is completely cracked or separating rubber.

Another thing to do...requires 2 people...brake torque the car.
Put the car in drive. Apply E brake. Push down on the brake pedal and gas at the same and watch the engine with a helper. Do the same thing in reverse.
If the engine moves excessively when you brake torque then you definitely need new mounts

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[dallam1]

Wow quick response....looks like u r a morning person like me who's up before the grand kids! Interesting suggestions and a good one about holding the brake on and putting the auto in forward and reverse gears. I'll have to get the misses to help though but it will b like waking up the junk yard dog....not looking forward to it. Another interesting comment u made was asking if the engine vibrated in park r in gear. The engine is velvet smooth in park r neutral but instantly changes to "egg beater" when put in gear. Thanks my friend

 

[UmmScott]

If it gets rough when in gear then it is definitely a mount, probably a transmission mount at that.

Youll have to check them. With my malibu with the 3.1L there is one by the serpentine belt. One right in front of the radiator fans, and one on the opposite side of that one behind the transmission. That one is extremely tough to get to but supposedly can be done.

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[dallam1]

OK thanks could very well b a mount but to find the bad one is going to b fun. My old Hyundai 4 cylinder had two bad mounts because the engine "clicked" every time I changed gears but never vibrated. Two new bottom mounts fixed that but I could see the engine rock as i gunned the gas not so with this Chevy though. I'll get under the car and take a look but not expecting to find much but I'll look anyway. Incidentally, this motor which had much fanfare from GM back in the day has two balance shafts so it should be smoother than something like a Vega 4 cylinder r "cast iron duke" Thanks again for ur help!

 

[UmmScott]

OK thanks could very well b a mount but to find the bad one is going to b fun. My old Hyundai 4 cylinder had two bad mounts because the engine "clicked" every time I changed gears but never vibrated. Two new bottom mounts fixed that but I could see the engine rock as i gunned the gas not so with this Chevy though. I'll get under the car and take a look but not expecting to find much but I'll look anyway. Incidentally, this motor which had much fanfare from GM back in the day has two balance shafts so it should be smoother than something like a Vega 4 cylinder r "cast iron duke" Thanks again for ur help!

Those 2.2 were very good engines.

The 2.4L twin cam engine...on the other hand...is a pile of junk. There's a reason they dont make them anymore LOL.
Those things were poorly designed and had oil pressure issues. They would self destruct in as little as 80k miles. Glad GM did away with those.

Glad i could help

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[dallam1]

about 7 or 8 years ago I bought my other boy an Alero with the 2.4 engine.....I liked it because it had pretty decent power but I do remember the engine sounded like a cement mixer and was a little rough... the misses hated it because of the noise. One icy night the boy took car of that car which was a creampuff! Anyway, I'll investigate the Classic like you stated and get back with u...after my coffee!

 

[dallam1]

Checked out the mounts. Three of them I could see but the fourth was a bear. The misses ran the engine put it in forward and reverse while I looked at the two mounts for and aft. Although there was movement it did not look too bad but I did notice a clicking noise from the rear mount as the wife switched gears. I'll look into changing that rear mount. With a little luck this engine will b as smooth as my old Hyundai.Thanks again

 

[DrivenDaily]

Check the plugs. If they're not GM's brand, AC Delco, then you may want to swap them out for a set. A number of other engines from various years seem to have the same reaction to non-GM-brand plugs.

 

[dallam1]

Gents; did more reading and combined with what Umm Scott stated I'm pretty sure there is a motor mount issue. That stated, I looked at the mounts very closely and will relay my findings and offer suggestions which might help u with a similar issue. First of all be careful doing this ....chock all the wheels, start the auto and put the parking brake on then put it in gear with the ac on. U should notice the interior "vibrating". As the auto is idling go to the engine...slowly and carefully reach down towards the back of the engine feel the inside of the rear motor mount.....b care of the hot exhaust pipe....u should feel it vibrating. Then feel the outside of the mount....it should b smooth with no vibrations. Go to the other mounts and repeat this procedure. If u notice the vibration on the inside AND the outside of the mount that should b the culprit. My outside mounts were smooth with exception of the front one. I have ordered a new front mount and after installation will report back. Incidentally, before I checked the mounts, I cleaned the throttle body and the idle air solenoid extensively.....vibrated as much as ever! Thanks gents

 

[dallam1]

Sad to state but after installing the front lower mount didn't notice any difference in the vibration at idle. It's possible that the mount I bought with it's hard rubber insert compound is causing the problem but I don't know. I did notice the original mount's rubber insert had completely torn thru so it did not hurt to install the new albeit cheap mount. I'll have some coffee scratch my head then read some more and go from there. Happy Sunday Gents!

 

[DrivenDaily]

It's interesting that you haven't made any comment about the brand of plugs at all. To me, it kinda looks like you got tunnel vision on the motor mount, which we've all done at one time or another.

Also, none of us asked and you haven't said whether the TB was cleaned, what condition the air filter is in, and if the CEL is illuminated.

 

[dallam1]

I'm now realizing there's lots of things that can effect the idle quality of r Malibu's. Freshening the plugs which I agree, can help, was completed early on. Also, I cleaned the TB and the idle air solenoid thoroughly. Along with the new mount, nothing has made the slightest impact on my boy's car's idle quality. R these old 2.2s just prone to shaking the seat and dash at idle? I don't know but I do know my old 2007 Sonata 4 cylinder with 200K miles idles smooth as silk. In my mind there no reason this little Chevy 2.2 shouldn't do the same especially with two counter balance shafts. Thanks DD for ur input!