[DrivenDaily]

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?

 

[DrivenDaily]

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

I have to LOL at that, and I'm truly glad that both @campb292 and @!Tommy explained the reason for my question. Please notice that I asked that after offering some input and requesting some more information for our members. And yet, your response to me ignores all of that just to take issue with the fact that I had the gall to ask whether you would offer more input or not.

I'm going to let your abrasive comment above pass since those two long-time and respected members stepped in. Otherwise I might have had a few more words to share with you.

So, now that that is out of the way, have you found anything new from your investigation(s) that might lead to a solution?

Were any of the ideas presented here of any use?

One other suggestion that we make for those who are kinda new: Consider modifying your signature and/or avatar to include the vehicle information. That will help others to refer to that instead of having to dig all the way back to Post #1, plus it'll save you having to include it if you start or participate in any other threads.

 

[DrivenDaily]

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.

 

[DrivenDaily]

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 . . .

 

[DrivenDaily]

Pictures if you can manage them, please!