1988 Firebird with a TBI 305
runs fine while in park or neutral but as soon as you put it in gear it drops rpm and dies
while off the brakes in drive it runs perfectly fine until you come to a stop and have to hold the gas to keep rpms up

 

It would probably be best to begin with cleaning the throttle body, IAC and its air passages, and cleaning the PCV system. All those contribute to the idle air rate, and even if that doesn't resolve the issue it will establish a baseline and remove those as suspects.

 

checked all the vacuum hoses because ive heard they can make it stall like mine is, the hose to what im pretty sure is the vacuum sensor is a little torn on the end. does anyone know where i could find a replacement its much smaller than normal vacuum hose

 

Without a measurement of the hose, it will be difficult to guess what a suitable replacement might be. Of course, once you measure, the replacement will become obvious.

 

Just take it to the store and match it up.

 

figured out a way to repair the hose that was messed up to the map sensor, works ok but the car still isnt running perfect. its fine at stop signs but waiting at red lights in drops rpm and dies if i dont press on the gas. also will die when going from park into drive unless i start moving right away. The pcv system is all fine except the breather filter is dirty so i dont think thats it but ill definitly get a new one.

What can i do to check the IAC system or any other things that could be making it run poorly

 

Check the P/N input to the ECM. Pin B10 (ORG/BLK). Should be near ground when in park or neutral, then go to +12 volts when in any drive position. Can do this with the parking brake set and key-on, engine-off.

This P/N input is used by the ECM to prevent stalling when the trans is placed into drive.

It is also a good idea to check the base distributor timing with the EST/BYPASS connector open. Stock is 0° BTDC, bumping it a few degrees can be helpful.

RBob.

 

Sorry its been so long i meant post the solution earlier

It was the ignition timing. helped with overheating issues and much more power now