94 Explorer-acts like starving for fuel when accelerating, but.....

When I accelerate hard, as in pulling out into traffic, the engine coughs and sputters. Loss of power. When I ease off then the engine
operates normally. This basically happens over 2000 RPMs.
I've added fuel additives, injector cleaners, octane boosters, you name it. The performance did improve somewhat. At least it quit dying when I accelerated. When that was happening, I would pull over and restart it, sometimes it would take a while and others it would start right up.
I have installed new fuel pump and replaced fuel filter. Fuel pressure is constant at 30PSI. Fuel pump relay OK. When I jump the relay as in remove it and and add a jumper for continuous operation the pressure continues to increase up to 40PSI. Vacuum tested OK.
Tested the coil pack and Ignition Control Module. Tested OK .
Replaced PCV, EGR, and a few other items.
Also it idles a little rough, intermittent misses, but smoothes out as I accelerate, slowly of course.
This happened once before, but stopped after it sat over night.
By the way, on the freeway I can get it up to 85MPH, but if I stomp on it, it cough and sputters until I ease off.
Appreciate any suggestions.
Thanks
Jim
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Easy to replace - the air filter. While your at it, clean the IAC.
Charlie

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Pulled the air filter, it's dirty. I'll replace it.
What's the IAC?
Also, it just died on me, twice, and was hard to start. An observation on that is that on restarting I did not hear the fuel pump cycle until the 5th try when I heard it cycle and then it started. What are the chances the fuel pump is bad after a couple of months?
On Sun, 11 Nov 2007 15:12:39 -0500, "Charlie Bress"

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replaced air filter and cleaned IAC , and I tested the IAC. Everything is Ok except now it misses at higher RPMs.
I'm beginning to think the fuel pump is going bad. It cycles, but not always. I pulled the relay and jumped it and sometimes it would not come on.. But would that cause it to act as though it were starving for fuel once its running?
On Sun, 11 Nov 2007 15:12:39 -0500, "Charlie Bress"

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First things first. What engine? Does the CEL come on? What is the fuel pressure at idle? The IAC won't cause problems over 2000 rpm.

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Hi Rob
Here's the answers to your questions.
4.0 V6. The CEL does not come on. The fuel pressure at idle is 30PSI.
Thanks
Jim
On Sun, 11 Nov 2007 17:14:43 -0800, "Rob Morris"

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pressure
as
on
How old are the spark plugs and wires? Do you have any white smoke when you first start it in the morning? Are you losing any coolant? I'm considering the possiblility of a leaking head gasket or intake manifold gasket. Is your temperature gauge reading normal?
Do you have any loose vacuum connectons, especially at the cluster on the intake manifold? If you do check for signs of transmission fluid which could indicate a leaking vacuum diaphram on the automatic transmission.
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The plugs and wires are 6 months old. I noticed yesterday some white smoke when I first started it, then after 5 minutes no smoke. Don't seem to have any coolant issues, but it does run on the cool side.
The vacuum pressure is fine and don't seem to have any vacuum leaks. I didn't notice any transmission fluid or coolant in the oil. How would I determine if there is coolant in the oil? Or am I misreading that part?
Regarding the head and intake manifold gasket, when I hook up the code reader I get a '10' which says there is a problem with cylinder one, but that has been reading that for a long time.
This morning, after driving for 15 minutes it started sputtering and coughing (like I was out of fuel) then died. It did that the rest of the way home, not all the time just occassionally. I wasn't driving it hard or accelerating, just driving 25MPH.
Thanks Jim
wrote:

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engine
dying
start
in
pressure
out
stomp
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After your comment on the white smoke I decided to pull the heads. And lots of anti-freeze residue inside the combustion chamber. I'm surprised it even ran. There was definitely leaking and I'm cleaning them thoroughly and will check for warppage. While I'm at it I'm going to replace the thermostat.
What a lot stuff to remove!!!! Took your advice and labelled everything. That will be a great help when putting it back together.
Once I get it back together and running then I will be able to determine if there is another problem, i.e. electrical or vacuum etc. No doubt the head gasket was a big part of the problem. Thanks for your advice.
Jim
wrote:

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