i have 85 gsl(rats nest is out), when you rev it up its nice and smooth , only when you take your foot off the gas it gets kinda shakey and rough, i checked for vacume leakes i found one so i pluged it up, so i revd it up still rough and shaky , aslo im idle is way to high ,from what ive read on the fourn it should be under or around 1, mine is at 15 at start up,but when you rev her up it goes up to 2 . so whats up??

 

Still sounds like you have a vacuum leak somewhere. Double check it. I think it may also have to do with the anti afterburn. Does it backfire at all when you take your foot off the gas at higher rpms?

 

Check your idle speed and mixture adjustment.

 

no it doest backfire