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2010 Chevrolet Malibu check engine light

The engine light came on and stayed on until I added a can of Gumout fuel cleaner at which the light went out. This repeated 3 times and was wondering what would cause this condition.

If you get the error codes read off the car the next time the light comes on and post them here, we could be of more help. AutoZone or O’Reilly’s will read the codes for free. Post the actual code P0XXX, not just what they they say.

My only guess at this point is a dirty injector or 3.

DTCFRZF P0171 Chevy Malibu 2010 LS 2.4L (B) 137,000 Miles FUELSYS1 CL FUELSYS2 N/A LOAD_PCT (%) 25.5 APP_D (%) 17.6 APP_E (%) 8.6 TAC_PCT (%) 7.1 EQ_RAT 0.999 TP_R (%) 4.7 ATT (F) 75 TP_B (%) 18.8 BARO (inHg) 28.6 CATEMP11 (F) 1252.40 VPWR (V) 14.855 LOAD_ABS (%) 25.8 FLI (%) 55.3 WARM_UPS 1 CLR_DIST (mile) 7 EVAP_VP (inH20) 0.084 MAF (1b/min) 10.6 TP (%) 18.4 RUNTM (sec) 110 EVAP_PCT (%) 10.6 RPM (/min) 709 VSS (mph) 0 SPARKADV (*) 4 IAT (*F) 100 ETC (*F) 180 SHRTFT1 (%) 12.5 LONGFT1 (%) 29.7 MAP (inHg) 12.1

DTC P0171 = The oxygen sensor on bank 1 has detected a lean condition.

Dirty fuel injectors can cause this code.

The Gumout fuel system cleaner may have cleaned the injectors.


That’s saying the engine computer is having to inject 12.5 % more gas to keep the O2 sensor reading the correct air to fuel ratio, than it thinks is should have to inject, based on only the air flow sensor. That’s for a short term measurement. The long term measurement is even worse, saying it is having to inject almost 30% more fuel than it thinks it should have. The only way the computer knows how much fuel it is injecting is by keeping track of the injector pulse times, and assuming the injector injects the amount of gas it should for that length of pulse. Injectors are rated as pounds of fuel per hour and the computer knows that spec for the injectors the car was built with. A 30 % long term fuel trim means there definitely is some kind of problem going on. it should be less than 10%. Clogged injectors seem to be at least part of the reason in your case, b/c the injector cleaning helped. But I suspect there are still more problems to discover. These are the original injectors that came with the car, right? If not, that could be the problem.

The most common cause of P0171 Fuel system lean fault for this vehicle is a dirty or failing mass air flow sensor.