my first jeep.........89 yj wrangler, 2.5 5 speed.......fuel pump, less than a year old, new fuel filter, new crank sensor, bottle of heet, and bottle of injector cleaner.....runs fine, then it feels like someone is putting the brakes on.....gets worse and worse, starts spluttering.....you can turn the key off for 30 seconds and it starts right back up and runs fine, for maybe another 20miles. then does it again. i caught the fuel from the filter, no trash or water.....cut the filter open and it is clean. No converter on the jeep. The jeep has started fine everytime except once, it didnt want to start. It is acting up more frequently.......any suggestions ?? Thanks in advance !!!