Hello,
My check engine light (02F150 8cyl 4.6) came on about a month and a half ago after getting a slave cylinder replaced and new spark plugs. Mechanic gave me the codes that kicked back, cleared them and told me to let him know if they returned. They did. I had the sensors replaced last thursday and the SES light came back on within a few miles of the shop. My maintenance guy at work threw his wicked cool diagnosticator on it and got the same codes again. Truck has not been running as smoothly as it was a short time ago. Bogs, shutters and hesitates slightly when accelerating between 1500-2000 rpms and runs a bit more smoothly above 2K. Engine seems to shudder when idling about 700 rpm.

I'm realizing now after searching through past posts that these codes don't mean the sensor is necessarily bad. Seems further examination is in order and from what I am reading, an intake leak, problems with wiring harness (for O2?) or an exhaust leak might be the places to start. Any other ideas? I am not mechanically inclined other than doing my own oil change. I Ihave another issue with my clutch, but I'll save it for another post...

Any help is appreciated.

Steve

 

Yep it pays to learn about what you are trying to do!
What do the codes mean? Both banks at there lean settings ((((in the PCM program)))).
How did this happen? Something happened that signaled for more fuel so the program says NO and leaned the system out. This is where the codes come from and what the codes means; system to lean both banks because the problem is common to both banks.
If this all happened after the clutch work I would be looking at the harness to the OX sensor for damage first because the OX sensors not working automaticlly makes the motor run rich as a protective measure preventing physical damage in the short term when the codes should mean to get the problem fixed soon.
Otherwise to much fuel is not good for the cats or cylinder walls in the longer term.
Next place to inspect is the intake system for 'unaccounted for air' that the system doesnot detect except for the OX sensors if they are operating.
You see, there is a complex relationship in the design of how the motor is controlled and is not to be taken lightly.
Good luck.

 

These are downstream/after the cats O2 sensor codes.

PO141 Downstream O2 sensor heater CIRCUIT fault, bank 1.

PO161 Downstream O2 sensor heater CIRCUIT fault, bank 2.

These sensors only monitor the condition of the cats.

Like Bluegrass 7 mentioned the wiring needs to be checked for damage from the clutch job.

Take a quick look at the fuse list in your owners manual. It will most likely show only one "HEGO system fuse", but if it shows 2, you need to check them both.

 

Thanks fellas. I'll be calling my mechanic today.

 

i wish people would post their solutions once they solved the problems. So irritating. I have this exact problem.

 

Sorry weasel. The first respondents hit the nail on the head. The O2 sensor harness got damaged when they put the trans back together. Took dealer to find the problem. Mechanic fixed at his expense. Good luck with your problem.