ok, USUALLY my car will kinda try to cut out and die sitting at a stop light at idle (like 700-800rpm) whether the clutch is pressed down in gear, or no clutch but in neutral...also whether the car is warm or cold. i was just driving home, and when i would slow down and press the clutch, the car would idle at 1800-2000 rpm. it stayed there until i got goin again. i sat at a stop sign for about 30 seconds just staring in amazement at my tach. ANY ideas on this?? i'll go out and start playin with stuff right now if anyone can help. thanks.

 

clean out your iac and set the tps

 

i have an 87 gt also and mine was not holding idle i changed the "throttle positioning sensor", "idle air control valve", and EGR. Also , i garauntee that you have vacuum leaks, i did. look up by your firewall for small hard plastic tubing running from the passanger side on the fire wall to about the middle of the engine. there will definatly be breaks there. also, there is a main vacuum line that goes from a vacuum tree on the firewall to the under side in the middle of you upper intake manifold. that tube is rubber and will be completly worn out and you will have to change it by taking off the upper intake manifold so you can get the old clamp off. that should fix the idle probs.