When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
i have a odyssey 3.5 and all of a sudden it started to run bad misfiring could hardly keep it running. this happened just after filling the tank so at first i figured i got bad gas. i still think this was it but it still is misfiring after 3 more tanks. i changed plugs and some said the egr so that came out and all was good there. i ran some b12 and seafoam thru it to see if that would help and i changed the plugs gapped from the box. this week i will pull the plugs and gap them to .030 and see if the changes anything. i had a hard time getting on this forum so the carfix forum was where i was getting the help.
the codes it shows are p0300 1-2-3-4-5-6 . that's it. some said bad coil pack but that doesn't explain all the plugs one said bad antilock brake module? some said fuel pressure but in my experience the fuel pressure is kept to around 50 pounds.
some even said the egr and a you tube said that so i tried it and nothing has changed.
it seems now to run ok at any cruising speed but during acc. it misfires and the cel flashes not the cel is on i have reset it a few times to see if i got any different codes. if it had a bad egr or the crank sensor or cam sensors were failing it seems they would toss a code even low fuel i have had toss a code but nothing. so can anyone here at the honda site give me a general idea or the fix. seems this would be the place to get the exact answer. i could believe bad injector but not all of them. nor all bad coil packs and or the small wires. but it is possible. if you say fuel then where is the valve to test the pressure i don't see it. i checked all the wires for breaks and shorts and i checked all the hoses i could find for cracks or off a port nothing. so at this point i'm stumped thanks
Highly unlikely that all the cylinders would begin to misfire due to this, but... When was the last time the valves were adjusted?
When you cleaned the EGR did you clean the main feed port as well as the small passeges in the upper plenum cover plate?
Highly unlikely that all the cylinders would begin to misfire due to this, but... When was the last time the valves were adjusted? i never did this. so honda in 04 on a car engine still requires valve lash adjustment WOW!
When you cleaned the EGR did you clean the main feed port as well as the small passages in the upper plenum cover plate? yes i did i checked and cleaned all the passages. i got about a tablespoon out of all them combined. this is the girls car and she had one of her friends check it and they changed one coil pack and now she said it is a bit better. but i still don't believe i would get misfires on every cylinder due to a bad coil on 1 cylinder. i think she is just thinking that. and if the valve lash is going out how would that cause misfires on all the cylinders. that is the part that gives me fits. is it that honda did not want to program the ecu better so they just made that code a generic one? i'm going to pull the fuel filter out of the top of the tank and see if it is getting plugged up this week it just may be she go enough bad gas thru it to slow the delivery down. it is way better than when it fiirst started but not gone. it cruses at any speed good but under any load it misfires. also today i will regap the plugs to .030 for starters and see if this helps if the coil packs are getting weak this will tell me a they will not have to work quite as hard. thanks
ok this is what i found i took the fuel pump out and the strainer was black and had some metal shavings in it my guess is the metal was not the issue but the black. then i took the pump apart and found the gas in the inside filter was black. so i think what happened is what i started saying she got bad gas and that clogged the filter. and as she drove the bad gas got diluted out and the total misfire went away but the misfire under load stayed because the filter did not let enough gas into the engine. so can you replace just that filter or will i need a new pump at this point? so can you get that filter or am i stuck with a new pump? thanks
does anyone happen to have a good location for an inline fuel filter? i think i may just dig out the guts on this filter and install an inline unit outside of just jacking the ar up and cutting the line has anyone installed a filter and where is a good place to install it for easy changing, as i figure i will have to change it more than one time in the next few months
05-23-2016, 12:42 AM
04 odyssey misfire code p0300 & 1-2-3-4-5-6
