How do I fix code p0171 on a 97 grand prix se?

Answer 1

any of the following could possibly be the problem

vacuum lines

pcv

egr

evap

maf sensor

leaky intake manifold/throttle body gasket

leaky exhaust

front O2 sensor

the vacuum lines are your most likely culprit; make sure there are no leaks in them along with the lines leading to the pcv valve egr valve and evap canister

If there are no problems with the vacuum lines or the valves/canisters connected to them, pull the maf sensor from the throttle body and clean it. check for exhaust leaks and if you can't remember the last time the front O2 sensor was changed that may be the problem (only use ac delco/denso if you decide to change it, not some other cheap brand)

If you still haven't found the problem spray carb cleaner or wd40 where the throttle body and upper intake manifold come together as well as where the upper/lower intake manifold join. If you hear a hissing sound or notice a change in rpms at idle you may have a leaky gasket there

hope that helps