[Jman]

I've been getting leans codes off and on for the past 9 months. I changed the O2 sensors about 8 months ago, the fuel filter and pump 9 months ago, and more recently the MAF sensor, PCV valve and hoses, the thermostat and coolant temperature sensor, and the EGR Valve. Everything except the MAF sensor and EGR valve I knew had to be replaced.

After clearing the codes each time, they come back on within a week, generally with high fuel trim ratios. Again today, just a couple days after replacing my EGR valve, the check engine light came on. But this time the fuel trim ratios seem fine (STFT 1 is -3.1, LTFT 1 is 5.5., STFT 2 is -1.6, and LTFT 2 is 7.0). I'm at a loss as to what to do next.

I have a 2001 Ford Explorer XLS with a 4L, V6 engine.

 

[WhatsUpDOHC]

I've been getting leans codes off and on for the past 9 months. I changed the O2 sensors about 8 months ago, the fuel filter and pump 9 months ago, and more recently the MAF sensor, PCV valve and hoses, the thermostat and coolant temperature sensor, and the EGR Valve. Everything except the MAF sensor and EGR valve I knew had to be replaced.

After clearing the codes each time, they come back on within a week, generally with high fuel trim ratios. Again today, just a couple days after replacing my EGR valve, the check engine light came on. But this time the fuel trim ratios seem fine (STFT 1 is -3.1, LTFT 1 is 5.5., STFT 2 is -1.6, and LTFT 2 is 7.0). I'm at a loss as to what to do next.

I have a 2001 Ford Explorer XLS with a 4L, V6 engine.

Do you have a plastic intake? Maybe a crack in the intake.

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[Jman]

Do you have a plastic intake? Maybe a crack in the intake.

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I've checked that but probably should take a closer look since I've replaced all of the hoses that had cracks.