http://www.youtube.com/watch?v=CThJT...ature=youtu.be



here is the video,

 

 

Hey...I get a turn.

Maybe your MAP sensor has gone nuts, or the vacuum source to the MAP sensor is leaking.

The ECM uses the MAP sensor input to aid in calculating the following:

• Injector pulse-width (rich/lean)
• Spark-advance programs
• Shift-point strategies (certain automatic transmissions only)
• Idle speed
• Decel fuel shutoff

 

No, it doesn't, and I should've re-read my post before hitting submit. I must've been thinking the MAP sensor- I was only on a couple of hours of sleep, so some crack may have helped. OP should check the grounds for the O2 and ECU/TCU as idle issues on a Renix are often from faulty grounds though.

Still... from what I gathered in the OP's first post, the idle wasn't high, it was eratic. Sure, it would rev-up but he also mentioned it dropped to 700rpm. If the O2 is faulty or a wire is chafing and grounding out somewhere then the ECU would be trying to compensate with a more lean or rich ratio, right? Jkshavoc, were you giving it any gas in that video?

 

yes i revved it a few times, but you can see how the rpm's are erratic and jump around. It sometimes stalls, when i took the video it wasn't that bad usually its worse. Thanks for the replies.

 

Don't give up on your XJ just yet..... You'll get it.....
Did you spray a little carb cleaner around your engine bay? Its a good way to help find vacuum leaks.
I'm kinda leaning towards that its a combination of issues. Is your tps adjusted properly? Are you sure all your vacuum leaks have been addressed? How about your throttle body butterfly? How does your intake/ exhaust gasket look? What about your exhaust manifold itself?
Just throwing things out there. Good luck.

 

I double checked all those things and nothing. Already replaced brake booster, egr sensor, tps sensor, map sensor clean throttle body and still the same thing. Could it posssible be the computer or the ignition system?

 

Im at the brink of giving up, and its a shame since the engine and trans are pretty much new. Just had them rebuilt about 2 years ago

 

Any friends got a ecm for a renix to swap. Im voting electrical issue by the way it twitches .

 

So should i change the ecm?

 

And how much would that cost at the junkyard? Thanks

 

That's not what I said ....If a friend Has a Renix Xj maybe you could swap ECM see if problem still exist.

 

Have you had any luck resolving this?

 

I really hope he did. Bless his little baby heart!