my 89 iroc TPI wants to idle up and down when stopped and in gear. Usually at stop signs I just put it in Park. It still idles up and down in park sometimes but not nearly as much as in drive.

 

I have a 92 camaro 305 RS and mine does the same thing. It doesn't matter though if mine is in park or in gear. Also doesn't matter if the motor is hot or cold. I have replaced the idle air control valve, the throttle postion sensor, and the fuel pressure regulator. All those have helped the problem but it is still there. Any ideas???

 

Ya, mine doen't matter if it is hot or cold either. I wondered if it might be the stall converter. or if my timing might be off.

 

I also have a mis-fire in cylinder 4 and the technicians at my work say that may have something to do with it. But once the engine is on for a minute it calms down and runs beautifully. When it is cold it runs like crap. Thats mostly the mis-fire though. Still stumped on the whole problem

 

I've had the same problem with my 350 TPI....i replaced TPS sensor and IAC valve....problem went away...it's probably stuck IAC (idle air controll) valve.

 

great... unfortunately for me I have already replaced those and I still have the problem. Any other ideas? my car is a 92 RS 305 TBI. Any help would be appreciated. thanks

 

It ended up being my fuel injectors. Runs great now and idles perfect since I installed new ones.

 

what brand of injectors did you use?, just curious. I'm having the same issue with mine, although its not that my injectors are bad, they are too big for the factory chip programming. I have 24lb LT-1 injectors in it, rough idle all the time. Im going to change mine back to stock for now so I can get it running right. That will make it easier to diagnose my terrible running hot issues. On a 80-85 degree day my cars temp is at least 230, at a steady cruise of 50mph, goes hotter at idle. I've replaced every cooling system component, still no luck. Any ideas? Lower radiator hose will start to suck shut if I give it a good rev in park, any ideas? No coolant leaks, fans work great, and like I said I replaced everything

 

I used the Ford Racing 19lb injectors for my 305 TPI. I found new ones on ebay for $175. Most places wanted about $260 for them. I couldn't believe I was using Ford parts on my car but everyone on here suggested them. And ford doesn't acctually make them just put their names on them. They are M-9593-C302 item number.

As far as your car getting so hot, I don't know. Unless one of your heat sensors are bad? But that just keeps the fan from coming on. I didn't see where you said anything about your thermostat but I'm asumming you changed that. It sounds more like you have a blockage in flow of your radiator fluid. But I wouldn't know where.

 

with your lower raditor hoes sucking shut, there should be a spring of some sort in it check the old one if you still have it or try to find one that would fit it, and the should prevent it from sucking shut and help the coolant flow easyer.