CEL reading 4 codes, please help!

Hey guys, I have been a member on here for a while but haven't been active much because work is so busy and I forgot what my username was so I made a new one...(sorry mods). So here is my problem, any help would be greatly appreciated.

I have an 02 with the 2.7. The CEL has been on for a while but only reading the p0141 code. I replaced both O2 sensors about 6 months ago and the code didn't clear. I have a new cat and two new O2 sensors coming this weekend so I'm gonna swap all of that. But the truck has been running fine with just that code....Bigger problems started this week. It has been idleing really rough when I start it, and if I don't let it warm up it bogs down hard when I first start driving it but it will get me around.

I read the code OBD and it gave me the same p0141 code (as usual) but it also spit p0171(bank one running lean) and p0172 (bank one running rich). ??????? It also read p1135, my code scanner asked my to input the model of the vehicle, I did, and its says "A/F sensor heater circuit malfunction bank 1 sensor 1". I am somewhat of a weekend warrior but I don't go much further then brakes, oil changes, maintainence etc. I do know alot about 12 volt and audio installation but under the hood....not so much.

Does anyone have any advice on where to start? I read something about cleaning/replacing the MAF sensor but I don't want to spend money with nowhere to start. Is this something I should go at myself or is it a more serious problem??

Thanks for reading all that, and help would be awesome. Thanks guys!

 

I'm not an expert on this but sounds like you have a bad Pre Cat O2 sensor. I would start there. I would replace that before your CAT too because that may not be necessary.

 

Agreed.....sounds like the upstream sensor has failed. Question tho......what kind of cat and sensors did you put in before? Because if they arent oem.......these trucks dont like aftermarket sensors and such too good.

 

I don't think he's changed the CAT just yet, just the O2 sensors. I've used aftermarket sensors (usually BOSCH) on other vehicles with 100% success so far, but never changed on my Taco yet. May want to check his wiring too for any damage.