Hey , my 4.0 (swapped in from a 93xj) started having intermittent low idle missing, and rough running. Revving will smooth it out, and its pretty much fine. Mostly occurs when starting it after stopping (ie warm engine) I cleaned the air filter. And it has a new poly tank fuel pump and filter from 2 years ago. One thought is that I forgot to put the brass filter on the pick up straw on the sending unit when I installed it. Wonder if fuel system issue ? Bad gas? Sound like any known common issues?
93 XJ 4.0 running rough
-
-
Possible vacuum leak?
-
Good point , I'll check that,
-
Any chance it's getting heat soak? That matches up with the warm start scenario. My XJ had that until I cut the hood for vents. I'd normally look at the throttle body for rough running at idle (clogged or bad idle air controller) but that wouldn't be my first guess for you... that's usually when it tries to stall when you come to a stop. The IAC valve would be closed because the throttle was open, but can't open fast enough to keep the idle smooth after the throttle closed.
-
Ive had similiar issues with bad tps, cps and upstream o2 sensors.
-
did you get this resolved? if so, what was the fix?
-
did you get this resolved? if so, what was the fix?
Pull your throttle body and clean it. If I get the lift bolted down this weekend you con bring it by next week. -
It still does it... but much less often, I ran a bottle of injector cleaner... Seemed to have helped. Been too lazy to check the codes, but I will check tomarrow.
Participate now!
Don’t have an account yet? Register yourself now and be a part of our community!