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1996 Xj tps questions, did my research


NAXJA Forum User
My xj is the notorious '96. I have a TPS code. Steady misfire at idle. Bad fuel mileage, reduced power. It sat in a field for 10+ years, rhd, I have 10k on the odo since begining restoration. I've viewed the charts/did my probing/research and this is what I'm coming up with.

Key on main power wire: 5.39 V
Key off main power wire: 0.39 V

Key on signal wire: 5.24 V
Key off signal wire: 0.32 V

Ground wire is, well, grounded soundly according to the meter.

If you put the probes in the following positions:

Black on ground directly on battery


13.23V on all THREE.

Tps unplugged, connector will show 0 resistance between all three wires.

I'm confused. Short? Ecm? What?

I still drive it. Everyday. 150+ miles per day. Abuse. Beat on it like a red headed step child. Stop and go without being shut off for 4-10 hours per day, WITHOUT ever being shut off. Pulling cars and a trailer, and 4 wheeling on the river bed/trails on the weekend. Misfire or not. It has assignments and will finish it. Misfire at idle only. Can't tell in the driving range. Only at idle. TPS code always. It has been replaced twice with no improvement. Ecm "reset" multiple times. Any suggestions?
The TPS is "Powered and Grounded" thru the PCM, also the signal wire goes back to the PCM. It (the signal terminal) should read about (from my FSM) Idle - 0.26 to WOT - 4.49 volts.
That's "positive" volts with 5 volts supplied by the PCM!
Electrical gremlins are a bear to
figure out, especially after sitting
in a field for 10 years...try swapping
out the ASD relay.
Funny my 96 was in a field for about 8 years.

TPS needed to be replaced (it had an error code)
It barely started.
guessing you have cleaned the throttle body.

this MIGHT HELP -->
Horrible single digit gas mileage and no error code. (Running super rich.)
MAP sensor was dirty. cleaned with specialty cleaner.
back to normal 16 mpg and runs great.
Here is video how to replace MAP (in a 96 xj ) https://www.youtube.com/watch?v=-zK61aak2wk

Instead of replacing, spray with Mass Airflow Sensor cleaner.

Do not use other cleaners because they will leave residuals that will foul the sensor.

takes 15 mins -rockauto has cleaner for $3.55

Symptoms: No error codes and horrible gas mileage. And yes.. using infamous K&N airfilter
Spray inside the vacuum port, slosh it around, drain it out and let it air dry for a while?