erratic idle
 

I recently replaced my timing belt and now the car idles erradically. I dosent over heat or seam to fire wrong but there is a definite vibration through out the car. Its worst at its lowset idle point and seams to be most smooth out at about 3000-3500 RPM (but not completely). The manual Im reading says I need to take the car to a dealer to get the belt correctly tentioned. If the belt was not at the right tention or the balance shafts were incorrectly placed could this bring out a nasty vibration? Will having the belt professionally tentioned fix the problem? To get the belt tight all I did was release the belt tentioner completely till the belt was really tight, and TDC is right on.

Yes, if the balance shafts are not correctly timed you can have some ugly vibrations. When I got my 924S, they were off; didn't know till I went in and replaced the belts. I re-zeroed the balance shafts, and was completely blown away by how much smoother the engine ran! Not just idle, but at the higher speeds too.

You might try re-timing the balance shafts only; that's what I'd recommend.

Could be balance shafts, idle stablizer, or bad engine mounts...

Considering that the balance shaft belt was removed to do the timing belt, this is probably the culprit.