Hey guys, new to the forums and new to working on my XJ. So I'm sorry if I am uncertain of nomenclature and the function of certain components.

I recently took my 2001 XJ Classic (Automatic) wheeling for the first time, and on the way back home from the wheeling spot, I noticed some inconsistent shifting and lurching while I was cruising down the road. I had a Check Engine Light come on, took my Jeep to AutoZone and ran the codes. I had a code for TPS low output, so I replaced the sensor and reset my ECU (battery disconnected for 1 hr, touch pos & neg terminals for 30 secs, reconnect battery, key to on, light switch to on, light switch to off, key to off). It drove fine for about 20 miles following this procedure, but once again my CEL has come back on and my throttle is acting just a little strange. I can shift through all my gears and cruise down the highway alright, but my throttle still seems very inconsistent as far as shift points, cruising RPM's, occasional bucking, etc. For instance, when cruising around 15-20 MPH when your auto trans should shift from 1st to 2nd, sometimes I have to throttle it to 2200-2500 in order for it to shift.

When I replaced my throttle position sensor, I noticed the metal piece that the sensor covers was covered in some surface rust, I didn't think much of it and threw the new sensor back on over it. Is it possible that this corrosion is causing my problems? Are there other things I should look for? i.e. dirty throttle plate, dirty IAC, etc ?

Thanks in advance guys!

 

Did you check the TPS connector for corrosion, spread or bent pins, etc.?

Did you replace with a Mopar OEM TPS?
Make sure the throttle body bolts are not loose and the gasket is intact not causing a vacuum leak.

Replacing the TPS is easy on a 2001....that is if the screws aren't seized.
Just got to make sure its 'keyed' in right to the throttle body's movement.

Far as the rust or corrosion, it depends on where and how much.

If all else fails, might want to pull the TPS and the throttle body return spring and check for any binding and correct movement of the piece that mates with the TPS keys.

 

Yes, when I replaced the TPS sensor I inspected the connector, all looked good. But, no, I did not replace with an OEM Mopar sensor, I replaced with a Duralast one which I am beginning to suspect is the cause of my problems. My CEL came back on and I'm willing to bet it's for the same low output TPS code. When you say check to see how it's keyed, I'm not sure what you mean. The "metal piece" behind the sensor I was referring to - I believe it's called the throttle blade - that is the piece I was saying I saw corrosion on. Is this piece what you're referring to about being keyed properly. How can I determine this?

I will most likely replace it with a Mopar sensor soon in addition to cleaning my throttle body & IAC and go from there.

 

Yes thats it, its the part that causes the TPS to rotate when the throttle is moved. It needs to mate properly to the two key tabs on the TPS. But i doubt thats the issue unless its out of whack or not working for some reason.

Off hand i don't know what the mechanism is in the throttle body that causes it to rotate with throttle movement. The corrosion could be causing it to bind, maybe something loose, bent or broken.

I think you're on the right track by removing the throttle body then cleaning it, checking it carefully and cleaning the IAC
Might want to consider replacing the MAP sensor also as preventative maints. while you're at it.

The Mopar TPS is a little on the pricey side but you get what you pay for.
Even if it doesn't fix the problem, you'll know its a quality part.

My original OEM TPS lasted around 300,000 miles and still working.
Replaced it only as a preventative maints. item with the new engine.

 

When it comes to engine management sensors, use only MOPAR.

 

Just in case anyone is viewing this for their own troubleshooting. My problem has been solved. I replaced my TPS once more with a MOPAR one, attempted to reset my ECU and test drive it again but the symptoms continued.

Long story short, I took it into a shop, they tracked the voltage running to my TPS while someone else drove it, and saw the sporadic voltage drop to 0 and back to the voltage it should be at. They found a section of bare wires on the harness towards the driver's side firewall that had been rubbed through. They repaired it and moved it out of the way. She's all good now.

 

amazing how small problems cause big ones lol.

 

electrical gremlins strike again....glad you solved the problem and thank you for posting the results