Engine Misfire #6 Cylinder
#1
10-09-2018, 11:55 AM
Engine Misfire #6 Cylinder
2011 Honda Accord 3.5L V6 Manual Transmission
Having issues with the 3.5L V6 engine.
June 2018 Pull away from stop light in first gear and the check engine light comes on along with the traction control light. They are flashing on and off. The engine has a “miss”. I pull into an auto service and leave the car. They call later and say engine is running fine and the check engine code is P0306, misfire on cylinder #6. They switch coils with #5. If it happens again on #5 then the coil is bad. They say the car runs fine and they clear the code.
August 24, 2018 Pull away from stop light in first gear and the check engine light comes on along with the traction control light. They are flashing on and off. The engine has a “miss”. I check the code and it is the same, P0306. I park the car at my house and restart it later. The miss is gone but the check engine and traction control lights are still on but Not Flashing. I take it to a different mechanic but he has no new information. The car runs fine again and I clear the code.
August 26, 2018 I purchase and install 6 new Hitachi OEM coils. Car runs fine. I also have 6 new spark plugs which I will wait to install. The existing plugs are one year old.
Sept. 30, 2018 Car has run fine so I install 6 new spark plugs
October 5, 2018 Pull away from stop light in first gear and the check engine light comes on along with the traction control light. They are flashing on and off. The engine has a “miss”. This time I put the car in neutral and turn the engine off with the key while coasting down the road. After about 10 seconds I restart the car using the key. The engine runs fine and the check engine and traction control lights are off.
October 9, 2018 Same thing, Pull away from stop light in first gear and the check engine light comes on along with the traction control light. They are flashing on and off. The engine has a “miss”. This time I put the car in neutral and turn the engine off with the key while coasting down the road. After about 10 seconds I restart the car using the key. The engine runs fine and the check engine and traction control lights are off. This happens twice today.
Then later the check engine light comes on along with the traction control light while I was sitting at a stoplight. They are flashing on and off. The engine misfires. I turn off the engine and restart it and the lights stay on solid but the engine runs fine.
Anybody had this happen or know what might be going on? Two shops had no idea. I haven't been to the Honda dealer yet. The P0306 code could be caused by many issues but I'm hoping someone has a clue because I don't.
Having issues with the 3.5L V6 engine.
June 2018 Pull away from stop light in first gear and the check engine light comes on along with the traction control light. They are flashing on and off. The engine has a “miss”. I pull into an auto service and leave the car. They call later and say engine is running fine and the check engine code is P0306, misfire on cylinder #6. They switch coils with #5. If it happens again on #5 then the coil is bad. They say the car runs fine and they clear the code.
August 24, 2018 Pull away from stop light in first gear and the check engine light comes on along with the traction control light. They are flashing on and off. The engine has a “miss”. I check the code and it is the same, P0306. I park the car at my house and restart it later. The miss is gone but the check engine and traction control lights are still on but Not Flashing. I take it to a different mechanic but he has no new information. The car runs fine again and I clear the code.
August 26, 2018 I purchase and install 6 new Hitachi OEM coils. Car runs fine. I also have 6 new spark plugs which I will wait to install. The existing plugs are one year old.
Sept. 30, 2018 Car has run fine so I install 6 new spark plugs
October 5, 2018 Pull away from stop light in first gear and the check engine light comes on along with the traction control light. They are flashing on and off. The engine has a “miss”. This time I put the car in neutral and turn the engine off with the key while coasting down the road. After about 10 seconds I restart the car using the key. The engine runs fine and the check engine and traction control lights are off.
October 9, 2018 Same thing, Pull away from stop light in first gear and the check engine light comes on along with the traction control light. They are flashing on and off. The engine has a “miss”. This time I put the car in neutral and turn the engine off with the key while coasting down the road. After about 10 seconds I restart the car using the key. The engine runs fine and the check engine and traction control lights are off. This happens twice today.
Then later the check engine light comes on along with the traction control light while I was sitting at a stoplight. They are flashing on and off. The engine misfires. I turn off the engine and restart it and the lights stay on solid but the engine runs fine.
Anybody had this happen or know what might be going on? Two shops had no idea. I haven't been to the Honda dealer yet. The P0306 code could be caused by many issues but I'm hoping someone has a clue because I don't.
Last edited by shipo; 10-10-2018 at 07:25 AM. Reason: Removed VIN to keep it away from web crawlers
#2
10-10-2018, 08:47 PM
The returning P0306 code after the coil swap ruled out the coil.
My advice for people reading this in the future:
Replacing the coils is a waste of money, because they were ruled out. More importantly, replacement parts can be bad out of the box and complicate finding the original problem. Same goes for the spark plugs. I think they last 100K miles, so the Aug 2018 replacement wasn't a bad if the spark plugs were due to be changed. The Sept 2018 is overkill.
A misfire one one cylinder can be missing spark, fuel, or compression. I'd put compression at the end of the list, because a mechanical issue should be present at all times.
My next step would be to swap the fuel injectors between say cylinders 5 and 6. If the code returns as P0305, then you identified the problem as the fuel injector. If the misfire code returns as P0306, then you ruled out the fuel injector and will need to do some more advanced tests. Do you have access to a scanner that can read live engine data?
My advice for people reading this in the future:
Replacing the coils is a waste of money, because they were ruled out. More importantly, replacement parts can be bad out of the box and complicate finding the original problem. Same goes for the spark plugs. I think they last 100K miles, so the Aug 2018 replacement wasn't a bad if the spark plugs were due to be changed. The Sept 2018 is overkill.
A misfire one one cylinder can be missing spark, fuel, or compression. I'd put compression at the end of the list, because a mechanical issue should be present at all times.
My next step would be to swap the fuel injectors between say cylinders 5 and 6. If the code returns as P0305, then you identified the problem as the fuel injector. If the misfire code returns as P0306, then you ruled out the fuel injector and will need to do some more advanced tests. Do you have access to a scanner that can read live engine data?
#3
10-10-2018, 09:07 PM
I believe the injector could be the issue. I've been reading and watching youtube videos about how to change them. Probably do that this weekend. Drove the car 60 miles today and didn't have an issue. I don't have easy access to a scanner. I'd have to get a shop to look at it. I haven't had much luck with the shops because by the time they look at the car it's not missing. The code may be there but that doesn't tell them much (just P0306). Is there a way to tell if the injector is bad visually? Is it possible to operate or test the injector with it out of the manifold? Anyway, thanks for the reply and I'll post if I find out more.
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