Hi!

I have throttle issues with my 1995 XJR. It has a rough and most often high idle and when I throttle it while driving it can sort of cough and go up or down in revs without me moving the pedal. It will also stick in high revs (about 1500 rpm) until I kick the throttle so it goes down. I have been dreading the TB removal job but I think it is the next step.

So far in my troubleshooting I have changed the sparkplugs, replaced the fuel filter, and ran the engine with "fuel system cleaner", I have cleaned the air intake and troubleshooted the MAF which seems to work. I have no fault codes in my OBD2 reader. When throttling from underneath by pulling the cable it returns well but high revs remain until pulling it again, so it seems to be inside in some way.

I will attach videos of the car idling hot and cold, fuel consumption data from the dash, and screenshots of RPM and Throttle position data. (I'm not sure how accurate it is because I have a very cheap Bluetooth OBD2 Reader.)

Do you agree that I should remove and clean the throttle-body or do you think I should check off other things first?
If I were to remove the TB Should I do it from the top or from below? What have you guys tried and which way do you recommend? What parts should I replace during the job and should I adjust the throttle in some way on the TB?

If I'm to do this job I wanna make sure I get the most out of it so I don't have to remove everything again.
Any help is very valuable.

Cheers!

 

The supercharged throttle body subject is documented ad nauseam in multiple threads.
In short, the least grim task is to remove it from below, but there isn’t an easy way.