Ford Freestar SES loses power under engine load

FREESTARBOMB

MEMBER
2004 FORD FREESTAR
6 CYL
FWD
AUTOMATIC
129,854 MILES

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.

Friday, February 18th, 2011 AT 3:18 AM

2 Replies

MJR346

MECHANIC
132 POSTS

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

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Friday, February 18th, 2011 AT 4:03 AM

RASMATAZ

MECHANIC
75,992 POSTS

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

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Monday, March 28th, 2011 AT 8:53 AM