1999 Tahoe Starts fine, then runs rough

[Magpie0663]

Starts fine, then runs roughAfter a few seconds. If I shut it off and restart it it will run fine for 10 seconds and then run rough again. I have already installed the air fuel sensor in the throttle position sensor also cleaned the MAF sensor.

 

[YukonGTmaster]

Does it display a "Check Engine" light? Are you able to read any trouble codes with a scanner or OBDII reader?

 

[OR VietVet]

Yea, any CEL? Even an engine that has a misfire can start and seem to run ok for just a little bit. Is the running problem in park or in gear?

 

[Hoesgottaeat2]

Greetings, and welcome to TYF.

Over the years I have had a couple of items fail on me that produced similar symptoms on mine…

- EGR valve
- Idle air control valve

Most consistent with symptoms you mentioned in my experience was the idle air control valve. A few times I was able to just remove it, clean it with some carb & choke cleaner and reinstall. Issue resolved.