intermittent rough idle

Chip682

New member
I have come across a new problem with my 92 4.0 cherokee. It has been intermittently idleing rough. Sounds a lot like a misfire. You can hear it through the exhaust. Probly been about a week since it started. Have been tring to diagnose with no luck. Currently has new Plugs/wires/cap/rotor/fuel pump. The fuel pressure has also been checked. There is no check engine light either. It only does this at idle. I am thinking it is a spark problem, maybe the Ignition coil? Cam sensor? Am i on the right track? Oddly enough it still gets decent milage so i dont think it is fuel related. But who knows at this point. Any input will be appriciated.
 
I think it may be a clogging injector. If i floor it for a sec it will clear up for a few minutes then go right back to it. I put some more Techron in it. See if that helps. Is there any way to take them out and clean them? I know i should replace but i have a real tight budget. I am going to try to pinpoint which cylinder is misfireing to narrow the field a little.
 
NOTE: The fuel rail will have pressurized fuel. Remove the test port cap and place a rag over the valve and releive the pressure by gently pushing the releif vave.

You can remove the fuel rail by unplugging the electrical connectors and fuel line then all the injectors will come off with the fuel rail. Clean all the nozzles.
 
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