I have a 1998 cavalier z-24 , after first frost last november my car wouldn't start, if you pumped the gas pedal it might start if you pumped the gas alot, but wouldnt idle on it'* own unless you kept feathering the pedal to keep it idling, once warmed up it was fine, turn it off same thing, so far replaced the coils, ignition control module , crank sensor,cam sensor ,plugs , fuel injectors and right now the ECM , in process of doing the relearn on the theft system also having a hard time with , do have a feeling that won't be it , also when you pump the gas you can really smell it, looking for any other direction? Thanks

Did you do any testing? Fuel pressure/ Throttle body clean?

How many miles on it?

How many miles on the spark plugs?

Is the air filter clean?

Have you done any testing with the MAF sensor?

car has 224.000 mi. on it, roughly 14.000 on rebuilt motor , plugs are new, just cleaned k&n air filter car doesn't have a MAF it does have a idle air control valve I did clean

My bad, that'* a MAP engine. Have you done any testing with the Manifold Air Pressure sensor?

What is the fuel pressure?

Also check the EVAP hose coming from the MAP, make sure no ends are rotting, or broken.

So far to date, I have replaced ignition control module , spark plugs , coils , cam sensor , crank sensor , fuel pump & filter , ground cable , and the latest ignition cylinder lock and have done the relearn process , it does start sometimes and runs great but most of the time it just cranks normally , thought it was a pass lock sensor issue until I changed out the cylinder lock, also read somewhere where the instrument cluster was tied into the pass lock also , not 100% sure on that one though, at this point looking for any resources to resolve this problem any help would be much appreciated Thanks

This is a classic symptom of the IAC valve sticking. And this is one of the many things you did not replace.

Take out the IAC, clean the TB and the pintle, and see what happens. Worst case, you can just replace it, but make sure you clean the area in which it seats into.

What Mike said above ^^^^^^^

I see you've cleaned the IAC, but haven't seen you clean the area where it seats. Might need to just replace the IAC too.

Did I miss where he said that? (EDIT, now I just seen it)

After re-reading what he originally posted, he also states he smells gas. This leads me to the fuel pressure regulator too.