Yes, The 87-90 XJ had a 4.0 engine with the Renix engine control. In 1991 the Chrysler engine control was used. Basically no sensors can be used between the two engines.
The sensor you are asking about is called the "throttle Position Sensor" or TPS. The TPS on the Renix requires calibration when you install a new one. There is a method using a multimeter to compare voltages. There are plenty of posts on calibration.
I replaced my TPS around 130,000 miles. The XJ ran better. I have concluded to change it every 100k miles. I set my TPS using the multimeter method, then I had it into the dealer and he checked it with the test set and told me I was out of calibraton but he set it for me. The only test set out there to "look" at the computer is the Snap-on MT2500 or the dealer scanner.
I am keeping my 88 XJ so I purchased the snap on tool off of ebay. If you go this route make sure you get data cartrages that do say JEEP on them so you know it will work on your XJ.
