Fuel Pressure

AV_1965

MEMBER
2002 FORD EXPEDITION
V8
2WD
AUTOMATIC
135,000 MILES

I've been trying to diagnose a slight miss in my parents' 02 Expedition, 4.6L. The repair manual I have says fuel pressure should be 50 psi (key on engine off and running). Does anybody have different specs? If so, what are they and what is your source? Thanks.
-Anthony-

3 Replies

RASMATAZ

MECHANIC
75,992 POSTS

Go to this link: https://www.2carpros.com/articles/engine-misfires-or-runs-rough

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Wednesday, July 13th, 2011 AT 11:41 PM

AV_1965

MEMBER
2 POSTS

Thanks for the screenshot. I tend to trust Mitchell over Chiltons or Haines, anyway. I should mention that I'm getting roughly 35 psi KOEO and 30 KOER. Looks like I may have to look elsewhere for the source of the miss.

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Thursday, July 14th, 2011 AT 12:33 AM

RASMATAZ

MECHANIC
75,992 POSTS

Could be one of the following:

1. Defective spark plugs
2. Inadequate spark/coil, defective spark plug wire.
3. Lack of compression
4. False air leakage.
5. Faulty fuel injectors.
6. Insufficient fuel pressure.
7. Contaminated fuel.
8. EGR valve that is leaking.
9. Oxygen sensors.
10. Throttle position sensor.
11. Manifold absolute pressure sensor
12. Mass Airflow Sensor
13. Idle air control valve

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Thursday, July 14th, 2011 AT 2:55 AM