I have 160,000 miles on my stock 2.0 (replacing those items that should be replaced at the correct intervals, i.e. I am beginning to think that the injectors may be the problem. I have these codes popping up on my OBDII tester. Notice that fuel injectors are not mentioned at all in the possible problems. *Purge solenoid hoses improper connection *Fuel leakage on fuel line from delivery pipe and fuel pump Your Mazda Manual must have been printed later than my July 2001 manual. * Base engine 'mechanical' fault affecting one or more cylindersĮngine running in closed loop at cruise speed for 2 minutes, and the PCM detected the A/F ratio remained leaner than the fuel correction limit in memory for 10 seconds during the Fuel System Monitor test. * Fuel control sensor is out of calibration (i.e., ECT, IAT or MAP) * HO2S is contaminated, deteriorated or it has failed * Exhaust leaks before or near where the front HO2S is mounted * Air leaks at the EGR gasket, or at the EGR valve diaphragm * Air leaks after the MAF sensor, or air leaks in the PCV system

* Fuel delivery system supplying too much or too little fuel during cruise or idle periods (e.g., faulty fuel pump, or dirty fuel filter) * One or more injectors restricted or pressure regulator has failed

* Vehicle driven low on fuel or until it ran out of fuel P0171 Adaptive Fuel Trim Too Lean (Bank 1) Vehicle driven at a speed of 17-74 mph at 1500-3000 rpm with the calculated engine load from 15-48% for 2-3 minutes, and the PCM detected the inversion ratio of the rear HO2S was close to the inversion ratio of the front HO2S during the Catalyst Monitor test. * Front HO2S or rear HO2S is contaminated with fuel or moisture * Front HO2S older (aged) than the rear HO2S (HO2S is lazy) * Front HO2S and/or the rear HO2S is loose in the mounting hole

* Catalytic converter is contaminated, damaged or has failed * Air leaks at the exhaust manifold or in the exhaust pipes P0421 Warmup Catalyst Efficiency Below Normal (Bank 1)

Mazda 6 p0171