Fuel starvation??? NEED HELP!

'96 Jeep XJ 4.0 auto

I just got a call for a new job on Monday, and my XJ isn't running. I've had issues with fuel starvation (suspect that's what it is) off and on for weeks. My local garage diagnosed it as a fuel pump, and I had them replace it, and the problem is still there... I didn't make it out of the parking lot before it began acting up. The service department it closed today, but I can buy parts locally all weekend.

Symptoms:
stumble and slight miss at idle
will lose power on acceleration
can't get above 50 km/h feeding it steady throttle, but can get up to 70km/h or higher by pumping the throttle
when it begins to lose power, it feels just like a plugged fuel filter and begins to backfire.

The problem is intermittent, and is not dependent on engine temp. They could not reproduce the condition at the shop, despite it being there 3 times. I've had it drive terribly for several miles, turn it off and back on and the problem is gone.The garage said they'd seen a number of fuel pumps fail progressively in a similar fashion, so they suggested replacing the pump. We tried a fuel filter first, and the problem remained. So, the pump and pick up screen were replaced. I don't know if the old screen was intact when it came out. There was no debris in the tank, and the fuel was drained and replaced with new fuel.

I've got spark at every cylinder. The TPS and IAC are new, and no check engine codes are coming up. The CPS is also only about a year old.

The fuel pressure regulator for this model is in the tank. I don't know what kind of symptoms to expect from a faulty regulator, or from a faulty relay. Could this be a wiring problem to the fuel pump, such as a faulty connection?

Thanks.

I think you need to go back and do some fuel pressure testing at the schrader valve on the fuel rail. Static and dynamic and compare to spec. With a new fuel filter and pump, the problem could very well be your regulator but you need data to confirm the fuel delivery problem.

So what are the symptoms of a faulty regulator? How would a faulty regulator cause this? I was thinking of this being more a matter of fuel flow (filter and pump) than an issue with pressure. Thanks.

is the filter new?

As stated, the filter was the first thing replaced.

oops.....

No big deal... And besides, I'm really just using you to keep my post alive.

Do you feel used?

Check your fuel pump relay. Had same issue on my 96. I swapped it with a different one. I think the A/C one is what I used. It's been fine since. Just make sure the numbers match as there are different amperage relay's there. It's in the fuse box relay box on the passenger fender. Check the wiring under the rear seat as mine was damaged by the PO not putting the jack away and it rubbing a hole into the wiring. I think that is what did the relay in.