I have a 1997 dodge ram with the 5.2 engine. I recently had to change the throttle position sensor in it. well this fixed most of the problems but i still get the p0171 code ( too lean, bank 1). I have cleaned the MAF sensor and even changed plugs and wires ( they were due a change anyways). I also started getting the code P0138 ( 02 sensor cicuit, high volts bank 1 sensor 2 ). Now the person i bought this truck off of had hollowed out the CAT and ran straight pipes on it. While trying to chase this problem down i relized he had unpluged the 02 sensor behind the cat.( possibly to not have check engine light on, i dont know) Anyways i have drove this truck for almost 3 years without a problem, until now. It is drivable but i can feel a miss in it while driving at highway speeds and my MPG have dropped some. Has anyone had a simular experience or does anyone have any suggestions on fixing this? Thanks

 

Welcome to DF.

I hope you mean you cleaned the MAP sensor, as these trucks don't have a MAF sensor. MAP sensor in front of the TB, IAC in the rear, TPS on the driver's side. MAP sensors aren't really serviceable, unfortunately, if they are bad, you replace them. They aren't that cheap either.

Not sure why it decided to come on now, but the P0138 means the O2 sensor is missing (which it is, since you said it was unplugged), malfunctioning, or is telling you the converter is bad.

 

Well to be honest i was calling it the MAF sensor because everyone that has tried to help me on it has called it that. I'll explain what it looks like and where it is . It is in the back of the throttle body has a tube that runs into the throttle body and one electric plug. I sprayed it down with sensor safe cleaner.( it had alot of carbon on it) i also cleaned the port it runs into. then i let the sensor, what ever it is, dry and ran the truck with it out to cleanup the cleaner inside the port. I thought that the computer should show some kind of 02 sensor error being that it is unpluged, and it runs like crap when pluged up so i'll leave it. I'm no mechanic by any means but am capable of changing out parts if i manageto run down the bad part. Does my description of it help you narrow down what part i am talking about? Before i cleaned it up it did wistle some while the truck was messing up but hasnt since i cleaned it up. Oh and thanks for the welcome and any advice you have for me.