I just bought a 99 XJ, and it is my first Jeep. I have just got done going through fluids & seals etc. I switched out the injectors, and I dont recall if there was a slight miss at idle or if it idled smooth. There is one now.I am used to v8s where there is a slight shimmy every few seconds. THere is a slight vibration at idle I can feel in the steering wheel. It does not carry through as I accelerate or rev it up. Seems like a very slight miss, maybe a ignition issue. I did not switch out cap/rotor/plugs, but I inspected an it appeared to be in good shape. I cleaned off some corrosion from the cap contacts. Or is it the new injectors (new style). Perhaps it is a trait of these engines that I am not used to. Any insight would help.

 

Inspect the motor mounts. Start the engine and look at the engine if you see the motor shaking it's the motor mounts.

 

I just replaced the motor & trans mount???

 

If there's no codes I wouldn't worry about it. These old Jeeps were never known for being comfortable cars. I actually have to get used to mine after I drive my Grand Marquis because it's whole different animal .

 

Visual inspection won't cut it for tuneup parts. There can be micro cracks in the distributor cap, plug insulator, etc.

Perform a FULL tuneup. Champion plugs gapped to .035, quality plug wires, cap and rotor. Don't buy cheap tuneup parts.

This is a new to you vehicle so getting that full tuneup is not that expensive and will establish a proper baseline for future tuneups.

Good luck and enjoy your 99!

 

Should do this to:
http://cruiser54.com/?p=60

 

Absolutely, Earl....good catch. I helped Cruiser with this writeup.

 

Good going!

 

A straight six should be silky smooth, but having said that mine does miss/shimmy every 4-5 seconds and always has done. I suspect leads too (it has had a new distributor cap recently).
I did the IAC a while back, it helped.

 

Yes, it drives fine, it just seems to feel like slight cam lobe at idle.

 

My 2000 is the exact same way. I have new plugs, verified the coil pack is free of corrosion, cleaned the throttle body and IAC, checked and clean all grounds that I could find and it still does it. Driving down the road it runs beautifully, just a slight hiccup at idle.