I have finally been getting around to working on my plow truck. It is a 2001 Ford F-250 4x4 with a 5.4 in it. The truck has 110,000 miles if that on it. I bought the truck last fall with the Service Soon light on and the previous owner told me it was the O2 sensors. I plowed all winter at about 7-8 mpg. I went to Autozone a couple weeks ago and had them check the codes to be sure. They told me "bank 1 and 2 running lean". So i bought 2 new bosch O2 sensors and replaced them on each side of the Y pipe. The truck ran great, started better, idled smoother, and had better power for about 4 days and it went back to the same thing as before with the light being on as well. I went back to autozone and they said "bank 1 and 2 running lean". So he told me the MAF sensor needs cleaned. I bought MAF sensor cleaner, cleaned everything up and it ran terrific again for about 3 days and now its back to the same thing. Runs a little rough, idles a little rough, and light is on.

Isn't there 2 more O2 sensors located up on top of the engine? Anyone have any clue where to go next? I am a diesel guy and a pre-emissions and pre-electronic gas guy to be honest with you.

Thanks,
TheBlueMule

 

The light is coming back because you haven't diagnosed and repaired the underlying cause of the problem.

Your fault codes are about the most common failure possible on these Fords. Plug your actual fault codes into the SEARCH tool and you'll find dozens, if not hundreds of the same questions with the same answers.

..and no, these codes cannot be caused by the O2 sensors.