Ford Freestar SES loses power under engine load

2004 FORD FREESTAR
129,854 MILES • 6 CYL • FWD • AUTOMATIC
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FREESTARBOMB
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My van starts fine and idles fine. Under acceleration or going up hills or even small grades, the engine misses and sometimes stalls. It also makes a weird noise when it misses. I have had the O2 sensor replaced, have put in new spark plugs and wires--what next? I read about the EGR valve but I don't seem to have the same symptoms as others who clean this and see results. Could it be a fuel pump?? I am at a loss and don't want to let the garage use my van as a guinea pig until they find the real issue. Appreciate your insight.
Feb 18, 2011 at 3:18 AM
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MJR346
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Ok. A real shop will use diagnostic tools to figure the problem out. But I have seen a few of these with coil pack problems cause missing under a load and usually on a fuel pump, the ones that have gone out on me, I felt it more on hard acceleration

EGR normally won't cause symptoms like this on that van
Feb 18, 2011 at 4:03 AM
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RASMATAZ
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Dunno if you had the computer scanned for code/s and came up with the O2 sensor-the problem here could be contributed by the following below

Could be caused by one of the following below

Oxygen sensor.
Catalytic converter.
Fuel injectors dirty/sticking.
Mass airflow sensor/Airflow meter.
Throttle position sensor.
Crankshaft position sensor
Knock sensor
Manifold absolute pressure sensor.
EGR Valve
Fuel pressure regulator leaking or defective fuel pump.
Fuel contamination.
Foul/defective spark plugs.
Open spark plug wires.
Ignition coil/Coil packs defective.
Incorrect ignition timing.
Cap and rotor.

Note:If it doesn't apply disregard it and keep testing


Mar 28, 2011 at 8:53 AM
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