the check engine light on my 2001 toyota tacoma came on and is giving me a p0171 code (system to lean bank 1)?

The mileage and the smell are symptoms, not the problem. A P0171 is most often caused my the MAF sensor, the one in the tube near the air filter. If you remove it (two screws), turn it over and look very carefully down inside the sensor, you will probably see two little bumps (the actual sensors) suspended by wires. These bumps will probably look very dirty, or fuzzy. If so, you need a sensor. The units tend to leak internally and contaminate the sensors by insulating them. The Mass Air Flow sensor then thinks there is less air than is actually going by, so the computer cuts the fuel down, which sets the lean code. You can clean it temporarily, but the issue is the leakage, not the dirt. You will eventually need a sensor regardless, about $150.

2001 Toyota Tacoma Engine

code p0171 is the air mas sensor & somtimes you will get

p0174 with it aswell regards Paul Toyota Master Technician

put a gas treatment and or octane booster and drive it real hard. Have someone reset the code before hand or take the positive battery post off for 5mins.

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if it is not getting enough gas, then you will have a lean fuel problem.it might be the gas filter partly clogged.