My 2000 v6 accord has 103k miles and about twice a week (going on 2 months) while the car is idling at operating temp I can hear a light "thumping" sound through the AEM V2 intake that doesn't have any rhythm to it and will go away after 10 seconds or less. Engine doesn't shake or have any lack or power or hesitation. No CEL. I am almost positive by the sound that there is only one cylinder in question. the plugs are NGK iridium plugs and are in good condition and this year used COP. The car has been maintained at ridiculously short intervals because I have OCD.

Ideas on a cause?

Anyone have any suggestions on tests i should do?

 

check mechanical timing first

can you upload a video

 

i will try to get a video with my gopro i just bought. Test run...

what do you mean check mechanical timing. timing cannot be adjust on this model.

 

ignition timing is nonadjustable on obd2 type engines but mechanical timing is totally different

 

so as I asked. what do you mean when you say mechanical timing? The timing belt certainly hasn't jumped time.

 

and u know that cause u checked it or just guessing ? normally sounds coming back through intake is mech timing off

 

I actually checked the belt because im at 103k and due for a timing belt change. couldnt get the crank pulley off so the old one is still on for the time being

 

You don't need to take the belt off, you just want to see if the timing is correct. You don't need to remove the belt to do that.

 

i didnt remove it. i was starting a timing belt service and had to put it back together. never took the belt loose. this problem started before this anyways.

 

Check fuel pressure if you have a gauge lying around to hook up. Any particular conditions that lead up to the misfires? Does it ever do it on a cold start, or is it only on a warm/hot start?

I heard random popping/misfiring on warm/hot starts before I swapped the fuel system out a few days ago. It's sorted itself out now but I would guess (based on it being the MY2000 and the J30A) that it's fuel related.

 

I have not found any particular condition which is why this has been hard to fix, doesnt happen near often enough to be able to recreate while I have time to work on it. It does however only happen on warm starts but its cold here in Indiana. Why would you change the "fuel system" and not the single failed/failing part?