P0171 and others

[blownb310]

Did you ever fix this problem? I'd like to hear what the result was. I've got a P0171 and don't want to waste money on an oxygen sensor if it might not be it.

Thanks

[cluelessindc]

From the FSM, PO171 monitors short and long term fuel trim. Determines if fuel system is too lean.
Causes: O2 sensor, PRC solenoid valve malfunction, pressure regulator malfunction, fuel pump malfunction, fuel filter or lines clogged or leaking, exhaust system leak, purge solenoid valve malfunction.

Good list! In my case it was the air intake manifold hose (rubber) connecting the outlet of the air filter to the engine air intake. It was cracked (underneath). Ran my hand around it to feel it, and the crack was obvious. Took 5 minutes to replace it - cost $49 at the dealer (2001 Mazda Protege 1.6 engine)

[invisibleman009]

I have the same problem right now w/ mine...code: p0171 and p0442.