I am having a transmission shifting problem with my 2004 Jeep Cherokee Laredo (4-WD, Inline 6 cyl)

My Check Engine Light (for the O2 sensor) is currently on – (P-0131) – No other codes are present.
Had it replaced several times in the past, and it comes back on within a day or two.

Recently my engine was slow turning over.
The camshaft position sensor code was on (P-0340)

I called my local Mechanic – who had worked on my car satisfactorily several times in the past -
They were running a free electrical inspection that week.

I have had minor electrical issues with this vehicle in the past. I have had to replace the tail-light bulb several times, and it seems to go out or function strangely from time to time. Also years ago had a cracked wiring harness in one of the front doors.

I told them about the code and took it in, and they ended up replacing the camshaft sensor.
Then the camshaft sensor code came back on again, they turned it off.
Picked up my car and paid them $286.57.

The next day, my car was sluggish starting again.
I went to Autozone to have the battery and electrical system checked.

The employee at AutoZone could not even check the electrical system because all of the cables were so corroded, and on positive terminal post of the battery was broken, with a indentation in the plastic battery casing next to it, that looked the same shape as a screwdriver blade ...... as if someone had tried to get the cable – which was heavily corroded and stuck – off by prying underneath with a screwdriver blade, rather than loosening the clamp.

AutoZone cleaned my battery cables and replaced my battery, which was only at 40% at the time.
Paid them $167.55.

There is no way that the mechanic who worked on my vehicle checked the electrical system!
Surely, if they had, they would have found the situation that AutoZone found approximately 24 hours later!

(Unless ... perhaps their guy broke the battery post and did not want to say anything, so just skipped the electrical inspection and replaced the camshaft sensor.....)

Unfortunately, because of the electrical issues present, I may have not needed that sensor replaced after all ... as an electrical issue can cause it to code .... but at this point I will never know.

I called and spoke with the assistant manager, who was going to investigate further, speak with the mechanic, and have the manager call me back.
I plan to follow up with them again this week.

Today, while driving in the afternoon heat, my car started having major trouble shifting from 2nd to 3rd gear. I had to take it up to almost 4,000 RPM’s to get it to shift.

In all other areas, it seems to run fine. Downshifting is fine, and shifting from any other gears is fine, too.

I saw a couple of YouTube videos, and Jeep Cherokee Forum articles that mentioned the O2 sensor issue possibly being an electrical wiring problem, or perhaps being related to shifting problems with the transmission.

 

Unfortunately, most "mechanics" are only parts replacers
Yes, your PMI directs shifting based on readings from the sensors and miss-readings deuterate shifting
Check the wiring harness coming up from the O2 to the fuel rail wiring harness - Chryslers wire shielding often deuterates letting the wires ground out on the exhaust manifold.
Often visual inspections will locate the frayed wire and electrical tape and wire ties are the only solution required. Look carefully over the wiring harnesses, while you're in the Neiborhood, look at the vacuum lines - obviously. dangling wiring or vacuum lines should be reconnected and secured