Oldsmobile/Buick Repair: 91 buick skylark, 3.3L, intake manifold gasket, skylark 3

Question
hey Ed,

my car is making a bad vibration but only when i am idling in drive.  in park it is just ever so slightly of a rough idle, but nothing i would normally really be to worried about.  i had a local mechanic take a quick look at it.  he tested the distributer, inspected the spark plugs, ran a diognostic, and just looked over the whole engine but came up with nothing that showed a problem.  This leads me to believe i have a transmission or possibly a converter problem.  i checked my tranny fluid level and the stick shows it is actually just a little overfilled (could high oil pressure cause bad vibes in tranny?).  i feel overall it drives ok.  a couple things to note though, about a month ago is when this vibration became bad.  it was a rough idle before hand, but there was a significant change at one point.  at this same time i noticed a small drop in gas milage and that my acceleration was slightly different.  when i am accelerating i feel the tranny sticks in gear for too long.  it will almost get to the point of bogging down before the tranny changes to a more efficiant gear(which i suppose would account for my declined gas milage).

Any ideas?

Answer
Hi,Jesse
Overfilled trans fluid wouldnt cause a vibration at idle,i have seen a torque converter do this due to balooning,the converter was failing internaly,though i would look into other engine performance issues,such as vacuum leaks,intake manifold gasket leaking etc,3.3 are notorious intake leakers and will cause idle problems,also injectors that are failing will do this also with a decline in fuel milage.

ED