well due to my dad slacking and me asking him for the past 3 weeks to help me i gotta go about doing this myself. my truck is throwing 2 codes, system running too lean bank 1 and system running too lean bank 2. i just replaced my fuel pump and fuel pressure regulator. i have a 98 s10 blazer LS. I'm thinking it maybe the catalytic converter is clogged but I'm not entirely sure since i cant get the bolts that connect before the converter to come out, if i could i would try driving without the 2nd half of my exhaust to see if it was the cat. The truck runs fine half the time but the other half the time it will accelerate extremely slow and then out of no where it regains the power. please if anyone knows how to fix this help me asap.

 

anyone?

 

check your upstream o2 sensors, either replace them or disconnect them and see if this resolves anything. upstream are the ones which measure exhaust o2 content, your downstream only measure the effeciency of the cats, if they are clogged, your computer would signal you through a code as well

 

O2 sensors have been replaced upsteam already

 

Try cleaning the Mass Air Flow, Intake Air Temp sensor as well as the throttle blade. Check air filter.

 

You could diagnose the issue:
P0171 - Fuel Trim System Lean Bank 1
P0174 - Fuel Trim System Lean Bank 2