I have a 92 RS 5.7L TPI Police Package and when its cold it doesn't like to start at all, spray a little gas in the throttle body and it fires right up. The next problem is when I'm driving, at a normal cruising speed through town at low idle it runs perfect, soon as I step on it, it falls on its face and spits and sputters. This happens weather its hot or cold, but as long as the cars wormed up it will start no problem. I have put a new fuel pump in, fuel filter, and just before it started acting up I had already changed, plugs, wires, coil, pick up coil, icm, ecm, prom. Not sure why its still running bad, Help please?

 

Check all you Vacuum lines. especially around the charcoal canister. I just had the same issue. It was a rotted rubber hose at canister.

 

I actually just changed every last vacuum hose friday, all brand new now. They were pretty dry rotted, however it didn't help.