My first problem! :-) Sort of... code + stall, then it cleared?

[Jeb Hoge]

OK, I threw a code last Friday night, and got it scanned the next day at Autozone. It was a P1131, which normally translates to a bad O2 sensor on the upstream bank 1. PITA to fix, yadda yadda. I cleared the code at that point, since I was at low fuel and wanted to make sure that it was a consistent problem and not something related to low gas, and sure enough, the CEL came back on the next day (with a full tank). I haven't rescanned it, though.

So, last night, I'm on my way home after picking up yummy CHIPOTLE, and as I'm approaching the turn to my street, I'm coasting in gear and realizing that it feels like my engine braking is more noticeable. As I clutch in to downshift, the engine dies. WTF? I crank the steering wheel into my turn, restart the engine while I'm rolling, and finish the drive home, no problem.

This morning, the engine fires fine, and on the way to work, the CEL turns itself off.

Seriously...WTF?

It's very rainy this morning, but warm. Could this be a WIRING HARNESS issue? I had it in for the 99M03 a few months back, but I know they only replaced the Fuel Charge harness and the battery cables...they did NOT replace the Engine Control harness, and I can prove it.

Ah...something else just occurred to me. I put a bottle of Techron fuel injector cleaner (fuel system cleaner?) in this tankful.

 

[Tony2005]

OK..It was a P1131, which normally translates to a bad O2 sensor on the upstream bank 1. ...

It's very rainy this morning, but warm. ....

It could be just water in the harness connector. I would just wait for it to come back again or just remove connector and clean it.

P1131 - Lack of HO2S-11 Switch, Indicates LeanWhen an HO2S sensor indicates lean at the end of a test, the system is trying to correct for an over-lean condition. The code is set when the fuel control system no longer detects switching for a calibrated amount of time.

.Electrical:
· Short to VPWR or VREF in harness or HO2S
· HO2S circuit shorted to Ground
· Water in harness connector
· Open circuit
· Corrosion or poor mating terminals and wiring
· Damaged HO2S
· Damaged PCM (other DTCs should be present)
Fuel System:
· Excessive fuel pressure (stuck fuel pressure regulator, restricted fuel return lines, etc.)
· Leaking/contaminated fuel injectors or fuel pressure regulator
· Low fuel pressure or running out of fuel (fuel pump concern, fuel supply line restrictions, low fuel level, etc.)
· Vapor recovery system (stuck VMV, etc.)
Induction System:
· MAF contamination
· Air leaks between MAF and throttle plate
· PCV system / Other vacuum leaks
· Improperly seated engine oil dipstick
EGR System:
· Leaking gasket
· Stuck EGR valve / Leaking diaphragm or EVR
Base Engine:
· Oil overfill
· Incorrect cylinder compression
· Exhaust leaks before or near the HO2S
· Secondary air stuck on

 

[Jeb Hoge]

Well, the CEL did come back. I'm dropping it off Monday morning at the dealership that did the incomplete 99M03 work...we'll have a little chat.

 

[Jeb Hoge]

And it's gone out again...when I dropped it off, it was out. Blah. Oh well, I told them to replace that rear O2 sensor while they had the wiring harnesses out.