Misfire confusion

[FORDGUY66]

Quick question. I have a '97 expy with the 5.4. I keep having cylinder 1 misfires. I have pulled the spark plug and its fine, replaced the coil pack, and replaced the o2 sensor. When I replaced the coil pack, it moved to #4 and after I cleared that code, it went to a P0300. I Replaced the coil pack in #4 and it came back to #1 again. Anyone got any ideas? I replaced the o2 sensor because the code kept coming up with the circuit being too slow. Solved that issue when I replaced the o2 sensor and that's when it moved to the misfire in cylinder 1. Any help will be much appreciated

 

[Whack]

How old is the fuel filter?

Ever check or replace the fuel injectors?

 

[FORDGUY66]

About 2 years old and I haven't pulled the injectors to check them but I checked to make sure they are getting power and they are. Haven't replaced any either.

 

[tonydiv]

I'd swap a couple of injectors and see what happens to the misfire.

 

[Captain Morgan]

Hey while we're on the subject, what are good brands and resources for injectors? Are the $30 rebuilds as good as the expensive ones?

Anyone have brands to recommend? Links?


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[FORDGUY66]

Would the fuel filter be a problem?

 

[Captain Morgan]

It could be if it blocked gas flow to your injectors, but the symptoms you describe doesn't lead me to believe that it is your particular issue.

If I were going to change injectors, I would change the filter at the same time.


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[Whack]

+1 to swapping the injectors..

There is an off chance that the filter is causing lower fuel pressure in the system. This would reduce the efficiency of the injectors, and if this is bad enough, misfires can happen.

The P0300 (random misfire) is really suspect, as lower fuel pressure in the fuel rail could cause it around the whole engine.

Swapping the #1 injector with the #2 would help.

Also are the #1 COP wire and #1 injector wire in good shape?

 

[FORDGUY66]

Ok and wires are in good shape. Which injectors are recommended? I found some on rock auto that were remanufactured for like $40

 

[Captain Morgan]

There's lot's in that price, that's probably what I'll go with, just not deal with core charges.