99 gmc

[98mazda]

Hi, I have a 1999 gmc 1500 and when it is cold it pops back through the intake. when warmed up it runs great. I have changed the temp. sensor and wiring still does it. any suggestions where to go next. It has 145000 miles on it. Thanks

[Supreme Pizza]

Huh. That is not as common on fuel injected engines. I believe that you might be running lean. If it were mine, I would clean the air flow sensor with the proper fluid, spray starting fluid around the intake looking for intake leaks, run SeaFoam or fuel injector cleaner through the fuel, check the air filter, check for engine codes, and maybe check to make sure that the engine oil maintenance is up to date and at the proper level. Do you drive the truck cold, or do you let it run for a few minutes before driving it?

[98mazda]

I do drive it cold. no engine codes. I have put injector cleaners in it and cleaned air flow sensor. could throttle body be bad?

[Supreme Pizza]

I don't think the throttle body is "bad", but cleaning it couldn't hurt. Just in general, you should not drive an engine that is cold (but you already knew that).