Hesitation, stumble, back fire on warm restart

[upstairsdave]

Greetings,
I have the 1999 Chevy Tahoe LT 4x4 that I have a hesitation. It shows up after I have driven the car and the engine has warmed up. After I restart the engine, it will start with no problem. Upon acceleration it stumbles and I hear the lean misfire in the intake. If I release the throttle the engine will stay running. It isn't necessarily a hard acceleration but more so when entering traffic and I wan to get going. I actually have to pull over to get out of peoples way. Once it is back to running a few miles, everything is OK acceleration wise. It only occurs on a warm engine restart.
Any suggestions would be appreciated. I don't think it's the fuel pump or it would cause loss of power all the time.
The car has 56 K miles on it.
Thanks,
Dave

 

[73shark]

Welcome to the Tahoe Forum. If you are getting a backfire thru the intake then probably either the spark timing is off or the valve timing is off.

 

[upstairsdave]

Hi,
The engine runs stron when cold. Probably still in Open Loop.
It only happens on a restart after getting gas or grocery shopping. then it only happens until I've driven it less than a mile then clears up. It appears to be a lean misfire. Maybe a MAF or CTS sensors. Coolant levels are OK. I drive and look at scan tool parameters after the engine is warm and all is OK. No codes stored either. I'm surprised I don't get a miss fire code. A code would be nice. I haven't checked the fuel pressure, but then again it runs great after this short episode of running with lack of power.
Thanks,
Dave