hi i have a 87 trans am 350-tpi auto and last night as i was coming home i noticed that the car was stumbling i would step on the gas slightly and the car wouldn't go until around 2000 rpm. also the idle rpm is usually at 600 last night it was around 500-800 rpm.

thanks

 

Sounds like a vacuum leak

Follow all your vacuum lines untill you find something unplugged. If it isn't a line spray some water (or starter fluid (bad idea)) around all your intake gaskets, plenum, runners, tb, etc and see if the car stumbles, if it stumbles then you found your leak.


Btw if you're spraying starter fluid it wont stumble, It will rev up.

 

also look at the TPS, mine was doing this until i changed it, it would not go until high RPMs also had the irratic idle like you described. just had one flat spot in the TPS and never threw a code.