Ok so I have a 99 Cherokee XJ that has the same 4.0L as my TJ Wrangler. It started misfiring/hesitating and idling really hard so I took it to the shop. They spent 3 days looking at it and decided that it needed a new crank sensor and throttle body. They also fixed in a leak in the vacuum hose. I got it home and it started doing the same thing again. They said to bring it back and they will continue to look at it, but I was hoping some of you engine savvy men and women might be able to give me some insight into what it might be. Might save me some money if I point them in the right direction.
I looked it up and some people said that it could be dirty fuel injectors, dirty cylinders, and/or bad spark plugs. I'm pretty sure it is misfiring in all but one cylinder. Thanks in advance for your help!