Hey guys hope you can help. 97 Xj runs mint but when I go in the trails and idle around in 4 low it gets all loaded up and breaks up. I get back out on the road and after a mile or 2 it clears up and runs fine. Any pointers or tips. Also just did cap, rotor, plugs, wires. Thanks

 

Clean any/all idle circuit components. Any CEL when problem occurs?

 

No CEL's at all. And it's only after about 15 20 minutes in the woods idlin around. When I changed the cap there was a small amount of moisture in it but it was a rainy day.

 

Changed what cap? Did changing cap do anything? Clean the idle circuit/components, the throttle body and sensors, check fuel pressure and go from there.

 

How many miles on your rig? Original O2 sensor?

When the upstream O2 sensor in my 98 crapped out, it would stumble/stutter just off of idle and backfire too. Never had a CEL either. New sensor fixed it right up.

 

175,000 miles, not sure about the O2 sensor, only idles rough when idling for a while like 20 min of stop nd go traffic or creeping in the woods. also even when running great when you give it wide open throttle it like bogs it down until you let off a little then starts pulling again.

 

mine did that until i replaced injectors.
if Id floor it hard in park it would bogs down some and mine would pop a little under the hood. but now shes smooth as hell.