Ford Aerostar Accelleration Problem

I've got a '92 Ford Aerostar that's giving me accelleration problems. Whenever I hit the gas, such as pulling onto the freeway, I lose power. It has nothing to do with the transmission (had that checked
already), I've replaced the fuel filter, checked the pump pressure and will be replacing the EGR valve this weekend. The lines are all clear.
Anything else I should check?
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[This followup was posted to alt.autos.ford and a copy was sent to the cited author.]
snipped-for-privacy@NOSPAM.verizon.net says...

Air filter? Spark plugs/wires/distributor cap/rotor? Throttle Position sensor? Vacuum leak?
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On Sat, 15 May 2004 07:53:22 -0500, Andrew Rossmann

Air filter is new, plugs and wires, etc. were just checked when I had a tune-up about a month ago. I'll check the others though.
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wrote:

checked or replaced? Did some one change timing?

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So what is the fuel pressure? Plugged exhaust?

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Brian Henderson wrote:

Where did you check the "pump pressure" and what was it? Did you check the regulator for free movement?
Rob
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On Sat, 15 May 2004 06:31:49 GMT, Brian Henderson

You are probably wasting your time with the EGR valve. It does not have the flow capacity to reduce power at full throttle with the RPM up. It is far more likely that you have a restricted fuel filter unless you have replaced it since the problem started. I have had a fuel filter foul within 10 miles after filling up with water contaminated fuel which resulted in OK acceleration at part throttle but, zilch at high power demands. This is why I always filled a gasoline filter with known good fuel before installing just like a diesel. Once the element is wet with fuel, it is much less likely to allow water contamination to pass to the engine in which case the filter has done it's job. If you have a load of wet fuel, it may take addition of fuel driers or cleaning the tank in a worst case. Another problem is a cat that has become plugged. A lean fuel mixture or some other problem with engine tuning can cause this. A plugged cat can usually be found with a vacuum guage on the intake which will show a falling reading as the engine speed is increased slowly. Have you have a diagnostic scan done? This can pay for itself in just one needlessly replaced sensor unless you have more time and money you want to throw at it..
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