Darrell7

Hello everyone, I just bought a 99 XJ and it is having issues. It starts and idles fine for as long as you want, but starting down the road it sputters real bad, sometimes it will cut off, but start right back up. I've replaced tps,cps, and dis.pick up. The one thing I do knowthat has been changed is the factory airbox has been removed and a cold air filter has been put on, I don't know if it affects anything or not, but I don't like it. I love the jeep but it is driving me crazy, any help would be great. Thanks.

Darrell7

I should also note that when it starts sputtering if you floor it, it will run like a screamin demon till you let off then the sputtering starts again.

Radi

Any codes set? Fuel pressure? Vacuum leaks?
What was done with the CCV plumbing when the factory air system was removed?

Darrell7

The cel light is on, but I've been to scared to try to get it to town, it's about 25 miles to the closest place to get it checked. I have no idea about the fuel pressure, I'm not much of a mechanic, I really just unbolt and bolt things back on.LOL. The ccv is hooked into the big hose coming off the intake.The reason I said something about the airbox was that I wandered if the air fuel ratio could be thrown off without the factory box, since it runs good when it's floored.I was wandering about the map sensor.

Radi

That CEL is probably holding clues to the problem. Can you borrow a scanner? Honestly you'll probably save the cost in parts you don't throw at guesses.

Jooman07

Yeah worst case is rent one from a parts house if you can get a ride to one. They refund the full amount when you bring it back. Once you pull the codes and find out what they are you'll be closer to figuring out what the problem is rather than throwing parts at it.

chickenbot

I had a similar issue with my 98 xj. My cel was on and the code was related to the o2 sensor. I changed them and it was not fixed. It turned out to be the negative power wire for the front o2 was not grounded. I just spliced in a wire and connected it to the negative battery terminal. Haven't had the issue since.