Hey guys i am new to the forum and i have a 2001 XJ automatic with the 4.0L . i bought the jeep for a steal and i absolutely love it . i am having a misfire problem tho. when i drive in the highway 60-70 MPH the check engine will flash ( misfire) and the jeep will keep on driving OK until it finally goes into LIMP MODE and the jeep will run like crap so i usually have to pull over and restart it and it will go back to normal for a lil while . driving in the city i get no codes ONLY HIGHWAY????

The only code i get is Cyl 6 misfire and no other code.

i have replaced:

New NGK spark plugs
New Coil-pack
New Injector (cyl 6 only)
Sea foam
compression test came out OK
Not losing coolant at all (head gasket)


Any ideas? next thing i will do is check all the wiring that i haven't done yet but any help is appreciated!

 

Yes, check wiring. If you can get a noid light, check the injector pulse on #6.

BTW, a flashing CEL means to stop driving it pronto, or cat damage can occur.

 

you think if i re-wired cylinder 6 injector to eliminate the possibility of bad wiring would be a good idea? i would just need to figure it out which wires are which at the ECU.

 

I've heard that some auto parts stores that loan tools, will loan out a noid light. I would test before I re-wired.