Ok, this one has me a bit stumped even though I have a possible idea on what is going on. The '97 has 238,000 but the engine only 80,000 some as it was replaced over the winter. Many of it's components were replaced before the swap proactively. It ran perfectly until recently.

What it is doing is at first, won't start, cranks ok and acts like it wants to start. If I push the issue, it finally does, but sounds like it is hitting on only a few cylinders until I keep the gas down and eventually it smooths out and runs ok again. It will go just fine until it sits for hours and does the same issue again. There are no codes and my Innova shows nothing in the ECM.

I suspect a bad cat here as I've seen severe performance problems and no codes before caused by just this issue. I just resolved one caused by a nearly completely clogged cat on my friend's Chevy. It was so clogged that it blew out his EGR. The only code it threw was for the blown EGR itself. The XJ sat for nearly a year until I replaced the engine and the cat is only a few years old, but it is possible that it went bad.

Any feelings on this?

 

Did you run a check on your fuel pump? Also may be a good idea to put an OHM meter on the ballast resistor if your vehicle has one!

 

Had a similar problem and no codes.I had a evap leak.just because there's no check engine don't means there's no codes.did you check anyways.pretty sure a cat would their a code.