Recently I replaced my head gasket and water pump. After assembly everything went fine and started no problem. I was really proud of myself and decided to clean the engine bay a little with some cleaner and water. When I was finished I let the engine bay dry overnight before I started it.
The next morning I went out started and the cel came on. I took it to oreillys to get the code read and the guy told me it was tps low voltage. Since I had replaced earlier this year it was under warranty so i got a new one. After switching it out there was no change. After some diagnostics I found on the web about putting a meter to the leads and back probing, the only off thing was that the signal lead was a smidge high. I shook the harness around found no difference in voltage. Is there something I'm missing? Where do I go from here? Any and all help is appreciated.

2000 xj stock 4.0

 

Try a Mopar TPS. The XJ can be very picky about that.

 

Since auto parts cant clear codes anymore (sucks) did you let it cycle through for a little while? i think 3 cycles itll sort itself out if it isnt throwing any issues and turn the light off automatically.

 

^this^

Also check the TPS connector for corrosion, cleaner contamination or spread contacts.

 

Also check the ground.

And just FYI - when it comes to sensors, use only Mopar. You can find them under the NTK or NGK label; that's who makes them for Mopar.

 

So I haven't changed anything yet but yesterday the cel waited 10 minutes before turning on. Not sure what the deal is with that but i'm still searching for a more reasonably priced tps, dealership wants 150.00.

 

Try Amazon.
Some Chrysler dealers there with over stocked parts are willing to dump them at a decent discount.
But make sure its a genuine MOPAR part.

I bought a MOPAR CPS off a Chrysler dealer selling on Amazon for a little more than half of what my local dealer wanted.

 

Go to ebay and type '2000 cherokee tps Mopar". There are Mopar TPS for less than $85 and free shipping. Or Amazon for less than that, even. And free shipping. Part #04874371AC.

 

So I put in a new mopar tps and the code went away but after driving a few minutes the throttle became erratic like it did once before when I mis-adjusted the kickdown cable (I think it's called that). So I readjusted it and everything seemed fine and then the cel came on again. Same codes low volt tps, and high volt o2. Its getting kind of frustrating at this point.

 

Doublecheck the TPS wiring and connector, including the wiring where it enters/exits the plastic shield next to the fuel rail. Refreshing the engine grounds never hurts. Test the TPS circuit. Key on, engine off. You can backprobe the connector using safety pins. Small ones.