Runs great cold
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Joined: May 2010
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Runs great cold
2000 F-250 5.4L Runs great when cold. Terrible missing once warm. Have error codes that left and right banks are too rich and misses in one cylinder in each bank. Book said Upstream and downstream O2 sensors / possible EGR. There is no downstream O2 sensor and no EGR. (I have looked vigorously for the EGR)
1. - No EGR?
2. - Possible injectors that don't work well hot?
3. - Converter?
Any thoughts? Any ideas appreciated.
Thanks.
1. - No EGR?
2. - Possible injectors that don't work well hot?
3. - Converter?
Any thoughts? Any ideas appreciated.
Thanks.
Super Moderator
Joined: Aug 2003
Posts: 25,479
Likes: 742
From: Isanti, MN
I think the misfires are caused by the lean condition.
Lean condition could be caused by...
Clogged fuel filter
Dirty or bad MAF sensor
Bad oxygen sensor
Vacuum leak
dirty fuel injectors
fuel pump
vacuum leak
Since it's only happening when it warms up it probably has something to do with what happens when the PCM goes into "closed loop" and starts to adjust based on what it sees from the sensors.
My vote is to clean the MAF sensor and see what happens. Then look at your oxygen sensors. If it were anything else I don't think it would run well when cold and start missing when it warms up.
Lean condition could be caused by...
Clogged fuel filter
Dirty or bad MAF sensor
Bad oxygen sensor
Vacuum leak
dirty fuel injectors
fuel pump
vacuum leak
Since it's only happening when it warms up it probably has something to do with what happens when the PCM goes into "closed loop" and starts to adjust based on what it sees from the sensors.
My vote is to clean the MAF sensor and see what happens. Then look at your oxygen sensors. If it were anything else I don't think it would run well when cold and start missing when it warms up.
