P0302 after fill up

first post been lurking for awhile. I have a 2004 taco 3.4, 5spd. 220K miles. I get a P0302 only after I fill up, clear the code and its fine until I fill up again. I have changed the plugs, wires, fuel filter, gas cap, #2 injector, swapped coils around. coils all ohm out within spec. I am at a loss. I have run seafoam through the intake a couple times. I have a slight miss at idle but has been like that for years. its not quite a true misfire though. kind of more like rough idle. runs fine otherwise. any other suggestions?

 

No idea about the code but maybe to try to help the rough idle. Clean the idle air control valve.

 

it sounds like your gas cap isn't sealing right, do you turn the cap till it clicks a couple times?

 

Or it is left running when fueling

 

i don't know that that would cause a issue, my cousins 04 pre runner 2.7l didn't throw any codes when he'd leave his truck running while filling up.

 

Never left running during fill up for several reasons. May try the IAC cleaning next.

 

Here's another thing to look into... http://www.tacomaworld.com/forum/1st-gen-tacomas/270050-3-4l-weird-misfire-issue.html

 

Thanks! i will try that too. its just bugging the crap out of me. the other thing it started about 15,000 miles after i did the T-belt. runs fine just annoying that i cant make the CEL go away.