Henderson98XJ

Hello!


98 XJ 4.0 Auto
recently installed Brown Dog poly mounts
and Daystar poly trans mount

Seems like these issues just happened out of nowhere and it has gotten worse very quickly.


First symptom, maybe started a week or two ago, after first starting the vehicle and driving slowly, at about 10 MPH the vehicle would feel like it loses the throttle. I would push the pedal down slowly and no response, it felt empty. I would let off the gas and when I accelerated again, everything would be fine. No issues for the rest of the drive. Didn't think much of it, adjusted throttle body cable but didn't fix it. Was gonna start trouble shooting and fix it later.

Now, yesterday, things went downhill quickly. Started the XJ, everything is fine. Drive to the store, great. Leaving the store, had the throttle response issue again. Drove to another store, on the freeway I realized the RPM needle was kinda floppy and sometimes jumping maybe 100-200 rpm. I believe this was not just the gauge but the actual engine RPMs because I could feel a bit of pull.

Got to the store, guy had trouble starting his car so I gave him a jump.. bad idea?

On the way home, car started acting very funny. Speedometer was off. Driving on side streets, maybe 25 mph.. speedometer said 40 mph.. and it would shoot up by 5mph, hesitate, shoot up another 5mph, etc. Also, when coming to a stop, it would go down very slowly.. driving 5 mph into a stop and needle is still on 20 mph.

Also, while on freeway on the way home, if I let off the gas, RPMs would drop to 1k or lower. When I would accelerate again, the needle would shoot to over 2k and drop back down to just under 2k (where the engine actually is)


This morning, took 3 tries on the ignition for it to turn over. Didn't have time to test the alternator, took the accord to work to be safe


Edit: Forgot to mention, car idles a bit weak now too.

What do you think is going on?

I have done some searches but it seems like 5 things have gone wrong at once..?

Plug in back of gauge cluster needs to be cleaned and plugged back in??
TPS needs to be replaced?
New alternator or battery?
Fuel filter or pump?
Clean injectors or swap?

How could this thing go downhill so quickly?

Any response is appreciated.

Thank you!

CCKen

A lot of sensors could come in to play here, especially with the speedometer acting up.

You could start by testing the TPS per that attached procedures.


Use a safety pin to back probe the connector.