1plunk

my problem started about a year ago, with my rear 02, threw the p0138 CEL. i replaced it and it turned off for about 3 months. This summer it came back. I replaced it once again. code came back on in a couple days. i crawled under and the driveshaft ate the wires (whoops) so i got another one.... still the code came back in a couple days. After that i said screw it. Until my gas milage was under 12 mpg. I took another whack at it and bought a rear 02 from the Stealership..... installed, code came back in a few days. Yesterday i got an NTK FRONT 02 from Napa, code came back last evening.

so here's what i've done so far:
3 rear 02's - current one is from the dealership
1 front 02 - NTK from Napa
traced all wires for both
checked the fuse in the Power Management box under the hood
unrelated issue - exhaust manifold was replaced with OEM from Napa
threatened to sell my jeep a couple of times hoping i could scare it back to health

the only thing left i could replace would be the cat. before i throw more cash at this issue, does this seem like the next logical step?

would really like my 16-20 mpg back

thanks in advance

~Adam

1plunk

well i finally did it last night. Got everything back to normal. I did a manifold awhile back and recently did a cat back exhaust that is against forum rules to discuss ...... so i needed an o2 bung in my new exhaust, i opted to delete the rear o2 sensor and install a simulator (not looking for a lecture on how "bad" these are) i wired it into the sensor side of the harness and ran it. No go. So i figured i had a fault in the wiring somewhere and having traced all of those wires at least 4 times and finding nothing wrong, i decided to use the tools at my disposal and delete the harness as well.

The simulator is tapped directly into the three main wire looms that enter the PCM, after careful calculations we got it right on the first try. after five 5 minute run cycles, no engine code, no pending codes, and one happy jeeper. This thing has been robbing my mileage for the better part of a year now. Ill check back in later with my findings as far a longevity test and my mpg gains returning.

Till next time.