Possible issues when low on fuel???

[OutFittedWRX]

Ok, so I've been getting the P0304 code on my 04' WRX for a while now, but I recently realized that the CEL light came off on its own after I filled up the gas. Nonetheless as soon as the car passes a little below the half way point on the gas indicator, the check engine comes back on. Maybe its just me, do you guys think this is the cause of the misfire (low on fuel).

** THINGS DONE **
all spark plugs changed.
2 coil packs changed (3 and 4).
one bottle injector cleaner.
Cleaned MAF.


thanks guys.

[EvoEatr]

How many miles are on the vehicle? How many times has this actually happened ( fill up CEL goes off, get below half tank CEL comes on ) ? Is the car actually misfiring like do hear/feel it? Does the vehicle seem to miss when your off idle like driving around? Can you hit target boost and if you can does it hold target boost? I have a couple things Im thinking of however I dont want to throw red flags without getting some more information fore as you know diag. over the internet is rather difficult haha...

[Anub1s]

Might want to do your fuel filter and give a little love to the pump sock and clean it off. There are times where they've been so clogged with gunk that people have had flow problems.

[teflon_jones]

Might want to do your fuel filter and give a little love to the pump sock and clean it off. There are times where they've been so clogged with gunk that people have had flow problems.

Yeah I agree, if it's happened a bunch of times, then I'd suspect the higher fuel level and resulting pressure is otherwise compensating for some problem with fuel getting to the engine. Most likely cause is a clog in the filter. Ever fill up when a tanker was filling the tanks?

[OutFittedWRX]

How many miles are on the vehicle? How many times has this actually happened ( fill up CEL goes off, get below half tank CEL comes on ) ? Is the car actually misfiring like do hear/feel it? Does the vehicle seem to miss when your off idle like driving around? Can you hit target boost and if you can does it hold target boost? I have a couple things Im thinking of however I dont want to throw red flags without getting some more information fore as you know diag. over the internet is rather difficult haha...

Ok, to tell you the truth I've just realized this possibility now so I really don't know how many times this has occurred. As for when the vehicle misfires, its usually when I'm driving around at 50+mph (the idle acts unusual when changing gears).... btw the car has around 144k miles.


Thanks again.

[EvoEatr]

Ok, to tell you the truth I've just realized this possibility now so I really don't know how many times this has occurred. As for when the vehicle misfires, its usually when I'm driving around at 50+mph (the idle acts unusual when changing gears).... btw the car has around 144k miles.


Thanks again.

How is your boost? does it hold target boost or does it seem to kind of surge or fluctuate a tad?

[nunez07c]

the boost holds target boost ..