duanewalker76

O.K. I've noticed that I get these trouble codes P0171, P0174 when I'm pulling up the mountain here where I live. This is the only time the check engine light comes back on after clearing it. I was thinking O2 Sensors but now I'm wondering about Catalytic Convertors. I mean it comes on when I'm under a good load and couldn't clogged convertors tell the computer that both engine banks are running lean?

Good old Bill

Sorry nobody has posted any help for us. I get the same codes every 2-3 weeks. Mine is triggered by early AM cold temperatures. Am having a MATCO tool man ask the techs at a local dealership today. What are you driving? Mine is a 2002, 4.2L. I pull my boat up an incline14 miles with elevation change of 2900 ft. Pedal is on the floor, 2nd gear (AUTO) 3000 RPM. But no codes. Start the engine with FROST on the ground, hello CEL.

dewman

I am not a mechanic, but I have always done most of my own repair work, mostly due to cost. Just throwing this out as a possible cause. Could it be that the thin mountain air is causing the lean codes? If it is, then I don't know that you will be able to solve the issue, other than to not "pull" up the mountain.

Another suggestion, you could send a pm to NGM, he is a mechanic and a moderator here. Ask him to have a look at your post and give his opinion.

duanewalker76

I might agree with you on the thinner air, but it hasn't always done this. It could have something to do with the 245,000 miles she's got on her. She's just now started messing up on me. what a truck!! I'm gonna replace my rear 02 sensor and clear the codes and see if that does it I've had a couple of mechanics around here tell me that is what it is. they said if I have no power loss then it isn't converters. I'll let you know.

gem

Check this regarding the MAF and those codes: http://autorepair.about.com/cs/faqs/l/bl903d.htm