Hi guys. Been on here for awhile now. This is my second post. Not sure if this is the right section. Anyways i have an 87 iroc 305 tpi 5speed. The car sat for a few years and it ran like **** when i took for a test drive, so i gave it a tune up. Changed everything, the fuel pump, fuel filter, pressure regulator, plugs, wires, cap, rotor, coil, maf, tps (adjusted), iac (adjusted), egr, the only thing i didnt change was the injectors but had them cleaned. After all that the car runs great, starts right away, idles good, but when im driving, if i take it out of gear and let off the gas the car stalls, but starts immediately when i turn the ignition, Could that be an injector problem? Maybe computer? Sometimes it backfires really loud too.

 

The problem with new parts is: people assume they are good.

Do you have any hard numbers or data logs?

What is your base timing?
What is your fuel pressure KOEO ?
What is Fuel Pressure Idling with vacuum and without?
What are your IAC counts at warm idle?
What is the TPS Volts?
Have you done a leak down test on the fuel system by a KOEO pressure up and observe pressure decay over 30 minutes or so?

When you say your IAC is adjusted, did you follow the procedure to set minimum idle speed?

 

I had a pretty similar problem with my wife's 1987 TPI last year. Replaced injectors, fuel pump, filter, IAC, TPS, etc. I got pretty frustrated with it and never was quite positive what combo fixed it, but I think taking off the new aftermarket IAC and putting the old acdelco one back on was what did the trick.
Wouldn't be the first time brand new aftermarket parts were bad out of the box for me. Worst thing about owning an old car is not being able to find quality repair parts anymore.