2003 Monte Carlo SS 224K miles, Vehicle cold starts fine & will run however long you want it to run till you shut it off & let it sit for 5 minutes. When attempting restart, I can smell excessive fuel smell & will crank until the battery runs dead. If I let it sit for approx 20-30 min, it will restart with no problem & will run perfectly till you shut if off again. I've installed a new fuel pressure regulator (thinking it was causing it to flood) & then found a broken MAP sensor & I put a new one on it. I've scanned for codes & nothing present & also vehicle does not have a security light present.
I've thrown enough parts at this thing & would sincerely appreciate any input on this issue. I've wondered if there is an issue where the vehicle is not getting fire when it's trying to restart, but I can't explain why it'll run as long as you want till you shut it off.