Do yourself a huge favor and get a fuel pressure gauge. Though you changed the pump recently, you are definately suffering from intermittent fuel pump symptoms, and the most reliable way to prove that I am wrong is to plug a gauge in, and stick it beneath the wiper and drive around til the pressure fluctuates. I fought this battle for ages, changing everything I could think of, (except the pump) and ran it thru 2 different shops, I had as much money tied up in this thing trying to fix it as I had in purchasing it.In one last ditch effort, I bought a gauge, and after 85 miles, the pressure started jumping around. problem identified. Mine would generally act up on the uphill after going downhill, and about 500 feet after leaving a stopsign or stoplight. Would idle either on all 8, or minimally on 5 or 6 cylinders, I could feather the throttle, generally enough to get the rpms up, in neutral, but placing in gear would pretty much kill it. While feathering up the rpms, to mash it would cause massive backfires out of both ends. Letting it rest for 30 minutes or so would clear things up, though the ecu would take a moment to stabilize everything to allow it to run nice again for awhile. (initial start was like it was loaded up with fuel) Very confusing, the gauge finally gave it away, no more trouble for the last 3 years or so, Other than one fail to start, which was sudden death of the main ignition coil, which I had a spare from the fuel pump fiasco... Good Luck!!! PS, there is no factory fuel filter, so that won't be the problem, unless it's been added.