Heavy Idle
 

The Alero has been exhibiting odd behavior recently, at first this would just occur every so often, where when I am in drive and at a stop the car idles and noticeably shakes including the steering wheel.

This has become more prominent and consistent as of late and worsens if I have the air conditioning on or am using the power windows. This almost leads me to believe it is an issue with the alternator but my knowledge on this is limited to Google results.

I have a video of this I can upload later if it might help. Insight or troubleshooting ideas would be appreciated.

not much to go on but

vacuum leak

Would a leak on the intake or around the throttle body count as a vacuum leak?

of course... anything that's not sealing the between the head and the throttle body is a leak

Any other places I should be looking for a vacuum leak?

I have checked around and on my intake and nothing appears to be leaking. I tightened the clamps down as much as I could and it might have helped some but it is hard to tell.

Does the car have a rough idle in park?

If your checking for vacuum leaks the ecomony way, just move your hand slowly and close to any hoses and places on the block like the TB. You'll feel the suction and the car's idle will smooth out when you block the leak.

The other way is to rent a "smoke machine" at the auto parts store. The vacuum will suck in the smoke ;)

if you cant afford a smoke machine rental, a piece of insense (sp?) would work... light it, let it smoke, then move slowly until you see if it gets sucked in anywhere...

It idles very nicely in park or neutral.

I will give the smoke idea a try, I wonder if there is any incense around the house...

Would the motor mount or the trans mount cause this? I'm having the same issue.

How many miles on the car?

You read my mind....that's why i asked how many miles. Sounds like a bad mount

Don't bother, it's not a vacuum leak.

I third looking at the motor mounts, mainly the one on the front (right side of the car) of the engine

mine does the same while stopped at a light
If I put it in Neutral or park it stops
I know the rear trans mount is bad and passenger engine mount
going to plan on replacing all of them
i also have a evap system leak having fun trying to trace that

147,000 miles. I will take a look at the mounts .

If it's hot, and the AC is switched on, the fans being on can cause some vibration at idle

I got 146,000 miles.

Anyone have these:

http://www.milzymotorsports.com/mms-...-engine-mount/
and
http://www.milzymotorsports.com/n-bo...mission-mount/

I have quite a bit of vibration in cool weather with all fans and the AC off, it gets increasingly worse with the addition of those factors.


Are there after market mounts for the ecotec?

I was doing some reading and it seems some diagnose bad motor mounts by keeping the brake on, putting it in drive (and then reverse) and giving it a little gas to see where the engine moves.

I don't know how much movement is considered normal (I would think none) but when I am in drive the front of the engine lifts and in reverse the rear of the engine lifts up a bit.

Post a video if you can. Also check the mounts for cracks/rips.

I didn't see any cracks when I checked them the first time. There are just the three I am looking at? the left, right and rear (which is the trans mount?)

I will take a video after work today and post it up.

https://www.youtube.com/watch?v=851e...e_gdata_player

After consulting with a couple of individuals their separate conclusions were that this is a healthy amount of movement, I would still like other opinions though.