YJ loses power and backfires

my 92 2.5l yj has an issue, maybe more then one. Once in a while it will start to lose power like it is running low on fuel, then will backfire. If I shift and get a hight rpm, it will go away, until I shift again.

This does not happen all of the time, sometimes in the first few minutes and other times after 5 miles. Some days it runs perfect....

Ideas? It has 188K miles

Thanks, oh wise ones...

A

Thanks. It's not burning any oil, pressure stays constant and I replaced the fuel filter about 30 days ago. Any ideas/

Thanks again