I bought a 2000 xj a few weeks, it is a 4.0 sport with 97,000 miles I have changed the oil, air filter, and the spark plugs so far. It has a rough idle, it seems to get better when you shift it in gear, and when it is moving, I read alot of posts on this site, and was wondering what to start looking at first. I have been checking the oil and coolant alot, because read about all of the head problems with this year. Thanks

 

Clean iac and tps. Seafoam your tb

 

Also clean the t-b (as stated above) and check the ev-6 plugs for corrosion (injector plug in's),Your plugs are gapped right( just checking) and you did use di-electric grease on the boots on the coil pack and made sure the springs are straight and able to reach the plugs right. Check fo vacum leaks.And run a top quality injector cleaner thru it.

 

I gapped the plugs what the haynes manual said, but I don't remember what it was, when I clean the tb can I reuse the gasket or do I need to get another one?

 

As long as the gasket is still in good shape yes, if you think even slightly that it's bad replace it so you don't have a leak , don't forget to check all your vacum lines, you can spray starting fluid lightly to find any leakers (motor rpm will change) becareful around exhaust, and tb ,The t-b will just give you a false find. Also check all your emission crapola.

 

413MAXWEDGE does your 2000 cherokee have that tin foil looking insulation on the intake under the fuel rail? Mine is all falling apart and was thinking about taking it off, do you think it will hurt anything? Is it to reduce the heat on the fuel rail? someone told me it was to keep stuff from getting on the exhaust manifold. It was a recall item. thanks

 

You need it, it is a heat sheild to help protect injector #3 from the heat soak issue, you should also get this stuff from dealer to wrap all injectors with (its cheap insurance)Part # 56028371aa (mopar injector heat sheilding) You can also get a new manifold heatsheild from dealer. these things are important to prevent heat soak. I also hooked the eletric fan to run when the key is turned on this helps out by allowing you to let the fan run when motor is off, like while waiting for someone in the store to let it cool down faster which won't let the heat to soak into the injector's creating the rough idle and vapor lock and CEL from coming on.Let me know if you need anything else.

 

Okay thanks, I will call and see if i can ordor some new, because that on their is all falling apart, and the injector heat shield too. thanks!