I recently bought a 2004 Accord 6 speed coupe, V6, and I have gotten numerous trouble codes, all in the P0300 to P0306 range. I know 300 is multiple/random misfires, and 301-306 reflect individual cylinder misfires. The car has 49,000 miles, and has an AEM intake and a Magnaflow exhaust. The car seems to idle and run fine, I have only wound it up 6500 RPM once or twice, and that seems to light up the CEL. I usually drive sane... but the CEL went on this morning after being parked on startup. Again, the car seems to drive fine and all, but I once again it lit up all the 300-306 codes. I can clear them, but they return maybe once a week ... probably not that much.
I don't have a factory shop manual yet, but if anyone has nay ideas, I am all ears at this point. I am not sure where to start...
Thanks in advance!
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there is an update for the computer. you need to bring it to the dealer and have the pcm updated. only a dealer scantool can update the pcm. ask them to look into service bulletin 04-042. they may charge .5-1.0 hour labor to update the pcm.

after the update and you get the car take it home, let it idle for 10 minute or so after fully warmed up with no loads(no radio, a/c, lights, etc).

now road test it exactly like this: put it in 2nd gear and accelerate to 2500 rpm and let the car slow down to 1000rpm by engine braking.

now road test it again, exactly: put it in 1st gear. accelerate to 5000rpm and let the cars slow down to 3000rpm by engine braking.


those 3 things are idle learn, low crank sensor learning and high crank sensor learning.

those 3 things should be done by the dealer after the update but most of us don't bother.

 

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Awesome! I will find some time to get it to the dealer and get this annoying problem taken care of.
Thanks for the quick reply!
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