Sometimes my 85 305 TPI will stall when i am slowing down to stop or when i am stopped.

Ive recently replaced my spark plugs, plug wires, distributer cap, and starter and the fuel pump is only 1.5 years old.

What could possibly be causing this?

-Thanks

 

Could you have a lean idle condition caused by unmetered air(vacuum leak)? Does the engine idle rough also? Could the EGR valve be stuck open?

 

Check your TPS and Idle valve

 

Go through the set minimum idle procedure, and if this doesn't fix it, verify that your ICV is extending and retracting. If the idle was off you will have to re-adjust your TPS.
I just recently help track an idle problem on an 86 where the ICV wasn't working properly so the owner adjusted the idle screw to keep it idling. Part of the whole mess was that he had a tear in his intake boot, after the MAF, that was letting unmetered air in the system also. After replacing the ICV and boot we had to go back and set minimum idle and adjust the TPS. Runs like new now.

 

The engine does idle rough and does not keep a constant rpm when idling. Could this be because of a vacuume leak?

Also, how would i go about checking if the egr were stuck open?

 

The TPS has been replaced, but im pretty sure the idle valve is original..would it be better to just replace it with a new one?

 

my car was dying on me when slowing down or making turns, almost got in wreck couple of times, replaced idle control valve, fixed the problem but still had jumpy idle, replaced tps sensor, now it runs great

 

my 92 camaro rs sometimes does the exact same thing. i had my head gaskets replaced along with alot of cooling parts about 7 months back, when i got the car back it has not overheated once but a new problem occured. it idles weird and acts up after i take it on long trips. RPM's jump up-down,stalls, sometimes it runs perfect and sometimes i can hardly get it home. i'v put a new MAP sensor, TPS, replaced plug for IAC(broken) and replaced 1 injector(broken), replaced the IAC and fuel filter. i suppose i'v replaced everything to do with fuel delivery except the EGR valve and fuel pump.

 

Turned out my erratic idle was caused by bad injectors (after replacing nearly everything else). It got so bad before I replaced them that my car would barely run.

 

Does speedo work correctly when this happens?

 

On TPI cars you cant access the valve to test it with your fingers. You can however use a vacuum pump to open the valve. With the engine at idle, opening the EGR valve should have a huge impact on idle quality if not stall the engine. If you don't get a big reponse to opening the valve, it probably means the valve is stuck open. It's best to use a smoke machine to check for air leaks in the intake, but carb cleaner or even brake cleaner also works. Carb cleaner will cause the idle to rise and smooth out whem it hits a leak. Brake cleaner will cause the engine to stumble. Brake cleaner is easier on paint and plastics than carb cleaner.

 

I would check the injectors as well. That it is what I finally tracked my problem to be. There are several threads on how to check them for leaks.

 

Sorry for the extremely late reply, havnt been on in a while.

Sometimes as slower speed, the speedo does seem to jump around slightly