Codes P0171 & P0174 on 2002 Chevrolet Tahoe

When it is cold

1 answer 5 comments
What engine?????
4.8
First suspect is vacuum leak at intake manifold. Not the only possibility though. Prob. need to get a mechanic to check it out.
I work part time at a shop. can it be check with carb spray
Cool, now we can talk motors! Yes that will work, check all the other stuff also like MAF may need cleaning, upstream O2's
Use a scanner, you will find it!
thanks