I'm a newbie when it comes to Jeeps, but it just so happens this week I helped a friend get his 97 4.0 running again. After miles of faithful running, and his beginning to do maintenance to it, it suddenly it would not restart after a trip to local store and he had it towed to his carport. Enter Me.
He, earlier, had already replaced plugs, distributor cap, and crankshaft sensor... to get rid of "occasional misfire". I found the camshaft position pickup coil (under distributor cap) damaged (Did he damage installing cap?) and we replaced. I went through the ignition set-up using markings on crankshaft pulley damper and block ... would not run!
I decided the crankshaft pulley had become too old to use for reference, and removed plugs, cranked shaft over and marked TDC using piston crown as indicator. Made temporary crankwheel markings with Witeout : followed set-up as outlined in Haynes and now it runs well. The rubber must have slipped in the crank shaft pulley .... but then, the Jeep has over 200K miles.