Hello all!

First post on this forum. Hopefully I'm posting this in the correct location.

I have a 2000 Jeep Cherokee Sport 2WD, 4.0L. Currently I have a hesitation or stumble during startup or in idle. When I start the car it initially rests or idles at about 1000RPM's. A few seconds later it begins to decrease it's RPM's to about 500RPM. It then stumbles from 500RPMS to 800RPMS while in idle. Shouldn't the RPM's be constant? The needle slightly moves between 500RPM to 600RPM...then sometimes jumps to 700RPMS...

I have installed an alternator, new battery, and installed new plugs. The coil ignition rail seemed a likely or smart replacement. Once the new rail was installed I started hearing a tick in the 6th cylinder. It's like an arcing. I'm not quite sure how it could be arcing though. I tightened it down fairly well, plus if you tighten it down it's flush against the block. Doesn't that ensure that you can't screw it up? lol!

Maybe there is dirt on it or something? It was difficult maneuvering onto the plugs, even with the throttle and coolant hoses/tubes off.

Any thoughts as to why I am getting a "tick" on my rail?