After warming up and restarting my 2000 jeep Cherokee 4.0 it goes into limp mode sometimes. It was in limp mode and I turned it off and restarted and it ran fine. Seems like it is an electrical problem due to the randomness. I reseated the coil pack and it seemed to help, but then it went back to running rough.

New plugs
Wrapped injectors and fuel rail
Checked grounds.

 

What is "limp mode"?

 

Flashing check engine light = limp mode

 

Limp mode is generally where the electronics of a system limits things. Like only starting out in 2nd gear, limiting power to keep from doing more damage.

Hence the confusion. So, you have a CEL on. Pull the codes.

 

Does it have a hitch in it's getty-up?

 

Misfire on cylinder 3

 

Okay. How old are the spark plugs? Brand?

 

I added two grounds as recommended by this page.

https://www.cherokeeforum.com/f51/cr...x-tips-153657/

the grounds helped but the Jeep still runs good sometimes and bad sometimes. Thinking about trying a new wiring harness. It seems to be electrical because sometimes it runs great.

I also installed these parts but same problem...

Coil
Throttle position sensor
cam position sensor

The plugs are new. Not sure on the brand but I got them at AutoZone for about 6$ each. There may be champion?

Thanks for replying.

 

Changed Bosch plugs to ngk and I think it is fixed. Thanks for your replies. Learned my lesson there. Bosch spark plugs make the Jeep misfire.

 

Keep us updated. which Bosch plugs?

 

I wonder if #3 was arching to the dipstick tube or something, then moving the wires during the plug change remedyd that. Guess we will never know. Watching it in the dark or swapping plugs around might have helped.