zshawkey

i have just got a 2000 jeep cherokee sport 4.0 168k miles im having a missfire in cyl 2 and 3 i have replaced the coil pack and spark plugs no help the injectors are also okay i do not burn oil or coolent can someone help?

Biofuels4Change

Check your cap and rotor!

If they are worn, burnt, or corroded...cheap fix.

Also try a new wire set. If your coil was bad none of them would fire.

zshawkey

Im a bit of a noob sorry whats the cap and rotor? And wire set for what? Thanks for the reply

zshawkey

Oh the cap and rotor for the distributor ? The 2000 does not have a distributor its the coil pack rail design

Ralph77

I own a '00 myself. What kind of plugs do you run? I bought mine running but not really driveable. Never had any misfire problems. Had been reading about it on the internet. When I got around to replacing the plugs I told myself that whatever was in there, whether it was expensive or cheap plugs, she was getting new of because some people seem to feel it is the type of plugs you use. They turned out to be cheap Champions Copper Tops. 438's.

zshawkey

I have ngk plugs in.. its misfiring in the same 2 cylinders though thats what seems odd to me is even after chamging the plugs and coil pack its number 2 and 3 cylinder still

Ralph77

Considering what the Champion 438's cost I am wondering if you should try them. Maybe $10 for the six. Also I am wondering if you are having the Heat Soak issue. Is there any certain set of circumstances that cause the misfire codes to appear? Last thing that pops into my head is the Coolant Sensor. The one in the thermostat housing. I know in a '96 it will affect how the Jeep runs. Have a buddy who owns one. Thing was running like crap. He did a complete tune up. Including air and fuel filters. In a '96 the fuel filter is not in the gas tank. Anyway, still ran like crap and then he figured out it was the sensor. Not sure if this would affect an '00 though.

Cherryokee

I think you'll get more help if you post this in the OEM Cherokee Tech section. And for what it's worth, you might want to expand your profile. You never know how much eyes-on & hands-on help you can gain from XJ'ers close to your location.

Does your XJ still have it's original "0331" cylinder head?

Problems with the 0331 cylinder head often start out appearing as misfires - issues beginning with cylinders 4, 3 & 2. I think that compression testing should be your first line of diagnostics (well, okay, second line after plugs). If you know the compression status of your engine is in-spec then you can proceed to other things with confidence. Otherwise, you're just whizzing into the wind.

Subsequent to that (or in-parallel with it) you may want to look into Cam and/or Crank Position Sensors (OEM only).

Good Luck.

BlueRidgeMark

What he said.