Ok guys, my car runs great other than this little bug when i first start it up in the morning. Here's what happens. The car starts right up, and will stay running, but acts like its stumbling on 5 cylinders or so. If i blip thye throttle a couple times, it hesitates but after a couple blips of the throttle it clears up and runs fine the rest of the day. I can't figure this out. You name it, it's new on the car. New injectors, new fuel pump, plugs are ac delco and not old at all, but still may be fouling from prior running problems i fixed, IAC is new, intake gaskets are new, tps is new and set at correct specs, changed distributors with known good one, and still has the same problem. MAF sensor is newer, all 3 relays on the fire wall are new. Timing is set at 0* tdc. I thought of maybe adjusting it. any ideas?!?!

 

I'm not very mechanical, seriously, but could it have something to do with the cold start injector? I know my car has one too but I didn't know if it had anything to do with the way the engine ran cold or not.

 

thats definitely something I should look into. Maybe it's sticking open somewhat and dropping too much fuel in?? I don't know. I wonder if I unhook it will it make a difference in how it starts? I'm gonna try that right now before i got to work. Good idea. By the way guys, I have no Troule codes in the car either.

 

Quite simply a stumble on cold start is incorrect air/fuel mixture. It could be mechanical in nature but it may need some re-tuning.

 

If it's not the cold start injector, try changing your coolant temp sensor.