You shouldn't be able to hear the fuel pump in the jeep with it idling. On some pumps that are of poor design, you might be able to hear them at idle, but definitely not at 5-10 MPH coasting. What you really need to do is get a gauge on it and check the pressure, anything else is a guess. To check for a plugged cat, you could drop the skid plate, and unbolt the cat next to the tranny and shove it out of the way and see if you have power again. If you do unbolt it, don't drive it for too long, the exhaust isn't supposed to be dumped out right there.