2003 1500 chevy silverado first set of codes was maf and lean on bank one and two
code 171 and 174.replaced maf and 4 oxygen sensors gave it a tune up change fuel filter and replaced plugs and air filter . now i still get lean codes on 171 and 174.
i checked fuel pressure and it is 55 to 65 on running car .checked for vacuum leaks with smoke test so i am at a loss i can clear codes with scanner and they come back.
After you changed the parts, you’ve found that they WERE indicatiing correctly. Can you get you money back for the MAF (Mass Air Flow sensor)?
The engine REALLY is running lean. Where can extra air (unmeasured) get into the engine intake? Vacuum hoses, for one. Don’t forget that there are several vacuum hoses. One, or more, could be allowing excessive air intake (brake booster hose; pcv hose; charcoal canister; cruise control; etc.). Also, the large air intake tube between the MAF and the throttle body could be split, or not sealed. Vacuum to the EGR valve, or EVAP sys hoses could draw excessivly.
Plug all the hoses, at the intake manifol that you can, and try again.
Maybe, the idle air control valve (iacv) is stuck wide open?
thanks,i will recheck.why is it not setting code until i reach about 30 miles and it never sets if it is above 57 degrees outside temperature