If you can help. I’m shooting in the dark here. My “99” Cherokee forgets what gear it wants to shift to over 3,000 RPM. I sprayed throttle body cleaner (mistake) into it it. Then shortly after it started this. Dirty sensor maybe. I don’t know enough about Jeeps to decide. Plus one of them looks like a pain to change.

Or it may be a vacuum leak. I don’t want to dive into that rabbit hole unless I have to.

Otherwise, it runs, drives and shifts perfectly. It always has for 220,000mes.

 

1) good chance you killed the tps with the cleaner. Any codes?

2 ) checking for vacuum leaks isn't a rabbit hole, it's normal maintenance on a 25 year old vehicle.

 

Into where?

 

Sprayed into the “throttle body”.

 

The cleaner should be pretty safe. Although the TPS doesn't like moisture, this cleaner usually dries without any residue. That said, symptoms started after that..

What do you mean with "one of them is a pain to change"?

You can differentiate electrical versus mechanical issues with your transmission by disconnecting the TCU and go for a drive going through the gears 'manually'. If manually gives no issues, its less likely related to a mechanical transmission problem.

PS: Do you have a multimeter available?

 

Many TB cleaners have acetone which will damage the conductive material in the TPS. Dunno why, but the TPS just isn't sealed as well as it should be. I agree, if Arklahoma has a voltmeter, it's pretty easy to test the TPS.

 

Also works to look at the throttle position data on the live data on your scan tool as you very slowly open/close the throttle ( ignition on/engine not running.... don't want to blow the thing up)

 

Thank you. When testing the TPS with multimeter. What do I look for?

 

Key on, not running, TPS plugged in. Negative on the meter to the battery or body. Stick the positive on the meter in the back of the TPS connector. I don't recall which pin is which, but you should have pretty close to zero on one wire, close to 5 on the other, and the signal wire should change smoothly between the two. Not changing at all or jumping rapidly means it's bad.