my car runs fine at high RPM's but when i let off the throttle the RPM's drop below 500 Rpm and the car dies. sometimes it will idle at about 500 but when you put it in gear it will die out unless you hit the gas right away. anyone had this problem before? any help would be apreciated.

1987 trans am GTA
350 TPI

 

check out your IAC.

 

whats the IAC?

 

The IAC stands for Idle Air Control. It's a little stepper motor right under the throttle body. To m knowledge, it helps control the amount of air the engine gets at idle. When they get clogged and dirty, the car often does what you described. There is a good tech artice about fixing it and adjusting the TPS here: https://www.thirdgen.org/newdesign/tech/tpimod2.shtml

Hope That helps. ~Arnold

 

When my car was doing the same thing i replaced the egr and some vaccum lines and that fixed it....