ok so i have a 01 cherokee sport all stock and it has a multiple missfire on cylinder 1 2 and 3!!! i just cant figure it out!! any help???

 

when did it start? check your dis order. If thats not it, replace plugs, wires, dis cap, and rotor

 

i got same problem except on 1 and 6.

 

Bad tps will cause multi missfire code. My experience thru 97, not sure about 01

 

its been doing it for about 6 months now and have replaced the plugs and wires but ill check the dis cap and order

 

2001 XJ's are coil on, there is no dis cap rotor or wires.

 

ya i was just thinkin bout that!!! and could that coil be bad and throwing it off??

 

There's a lot of things tha can cause a misfire.

The first thing I would check is the plugs, check them for carbon tracking on the white part of the plug. It will look like a black line running from the top of the plug down the porcelin. If you see this it is a good chance that the spark from the coil is "leaking" out and not letting the plug fire properly.

Next are they the correct plugs for that engine? The emissions tag located under the hood has the correct spark plug part number and gap listed right on it. Use those plugs and gap them correctly.

Fuel pressure must be in spec 55-60 psi

The foil debris/heat shield that covers the intake on most 4.0 engines can direct the heat from the exhaust at the injectors and cause a misfire. Most of the time it is just the #3 cylinder and there is a TSB out to insulate the #3 injector.

These are just a few Ideas, you could also do a compression test and a cylinder leak down test to see if it something inturnal to the engine like a sticking valve, broken valve spring, or heavy carbon build up. This would be a good idea if it were isolated to one cylinder, you probably won't need to go this far.

 

thanks for the ideas i have some free time the next couple days ill tear into it