Strange problem with my 99 xj. When I first start up and accelerate to go it acts like it wants to stall then all of a sudden it takes off? It only does it when I first start to go after a fresh start. I can run stop and go for hours and it will never do it again.


Any ideas?


thanks

 

So, it's likely temp related, given it only does it when 'cold'.
Could be a few things,so time for testing, diagnosing and treatment.

Without knowing what you already have done regarding that, here a few thoughts on what to do.

Clean the Idle Air Control (IAC)
Clean Throttle body and valve
Test your TPS (look up on here for instructions, recent thread on same issue)
Take a fuel pressure on first start of the day

Often Not directly related but contributing: when was last tune-up done ?

See how you go with this.

 

My '96 did that for the longest time. About 10 feet out of the driveway it'd feel like it was about to stall, then take off again. Then it was fine until the next morning.
I changed the TPS and CPS for other reasons and the problem stopped. I don't know which one of them was the culprit.

 

My '99 did exactly that. Changed my upstream O2S and it fixed it.

 

Could be tons of stuff. I did everything listed above and it got a little better with everything. The final straw turned out to be replacing my cracked exhaust manifold.

 

Sounds like a marginal O2 sensor. How many miles on the rig?

 

Well, as you can see, you should have several by now. A nice wide variety of claimed culprits. good luck! Let us know what did it for you

 

Thanks for all of the good ideas.

I am replacing my cracked exhaust manifold this weekend. See what happens.

I will keep you posted as I do different things, thanks everyone.

 

That should fix it. Had that problem on my honda. Once replaced it was fine. You may want to change the o2 sensor as well

 

Last weekend I did the Durango steering box upgrade and installed the junk yard header and it did seem to be running better until I was on the highway and she started cutting out and CEL. Codes showed TPS & O2 sensors. Replaced the TPS and problem is gone. One sensor came right out but rear one is being an *** so I need to get a torch and heat it up to get it out.

So I guess you could say the problem is gone....Will know more when I get the sensors replaced and see how she does with some miles on all of the replacement parts.

 

Roler can tell you how easy that one is

 

lol. Yep, I can still hear it grin at me when I walk around the Jeep.....

 

My 1992 had the same problem a few months ago. $30 throttle position sensor fixed it completely.

 

If you've never done it before I highly recommend you give yourself more than enough time for the exhaust manifold replacement as you will probably need it. Its a huge PIA and definitely something you wanna get right the first time.