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2000 Accord 4cyl. misfire

Hi everybody,

I have a 2000 Accord LX, 4 cyl. that has decided to misfire and make my live miserable. Got the first Check engine light while driving on highway, so the next day I went to a local mechanic that read the code as “misfire cylinder

#2” and changed the plug wires. Everything ran good for about a week, then it started misfire again. This time I replaced the rotor, distr. cap and spark plugs and cleared the Check engine light myself. Again, it was good for another five days, then started to misfire again, but only in idle and no Check engine light came on. If I press the gas pedal just a little, the misfire will go away. I brought it to a dealership yesterday, and had them take a look, but they were are clueless. Today I plan to changed again the plug wires - since the local mechanic put some cheap aftermarket ones, but I don’t really think is going to make a difference. I heard other people that it could be an injector isssue, but the dealership mechanic said the injectors are ok. I have no idea, I’m lost and I still love my Accord.

Please help.



A misfire in a cylinder can be caused from many things. Low compression, worn secondary ignition components, bad injector, vacuum leak, or carbon deposits.

The first thing to try is the next time you fill the gas tank, try adding a can of Sea Foam to the tank, and see if this improves the condition. This will do two things. If there’s a dirty injector this will clean the deposits from the injector. And, if there’s carbon build-up on the backside of the intake valve this will help to remove it. If you find an improvement when doing this, add another can of Sea Foam at the next fill-up.

If after the first treatment of Sea Foam shows no improvement, then a decarbonization of the engine with Sea Foam may be required if the carbon deposits are excessive on the valve(s).

To do this, get the engine up to operating temperature and turn off the engine. Disconnect the brake booster vacuum hose at the brake booster. Adapt a smaller hose into the end of the brake booster hose with the other end into a can of Sea Foam. Pinch this hose off with a pair of pliers. Have someone start the the engine and bring the idle speed up to 2,000 RPM’s. Slowly open the pliers so that the Sea Foam begins to be drawn into the engine. It’s here where the throttle must manipulated and the pliers are opened and closed to prevent the engine from stalling. Once all the Sea Foam has been drawn into the engine shut the engine off and wait a half hour. Reconnect the brake booster vacuum hose. After a half hour has passed restart the engine and bring the idle back up to 2,000 RPM’s until the smoke out of the exhaust clears. Drive the vehicle to see if there’s any improvement.


Eddie, I would check - or have someone check - the compression. Its reasonably quick & easy in a little 4 cyl, and will allow you to eliminate disaster as a possibility before pulling your hair out with smaller things.

If compression checks out, I would wonder if you might not have had 2 different problems. I.e. are you sure that what you have now is a “misfire” - or is it just a rough idle? I’m guessing that you’re stuck on misfire b/c of that code, but if I understand you correctly the check engine light has not returned since plugs/wires/cap, etc. As such, maybe the remaining problem isn’t misfire.

The reason I say to consider that is that the symptoms you describe now sound like a vacuum leak. There are terrible to find, but cheap and easy to fix.

I would also start worrying about fuel too. When is the last time you replaced the fuel filter, for example? I’m not sure what the dealership did to eliminate fuel injectors as a problem, but I wouldn’t necessarily take a faulty injector off the list. If you do get a code again for cyl 2 you could try swapping the #2 injector with another to see if the misfire moves.

Thanks for the quick replies guys. Much appreciate it!

I will add some Sea Foam, and I’ll monitor the condition.

I am too thinking of a bad injector, or a vacuum leak. As for when was the last time I changed the fuel, is never. I have 153,000 miles on this car and I have also noticed that during winter time a have a drop in mileage of aprox. 10 %.
I keep saying it’s a misfire because it feels like the engine is sputtering, like a wire is broken but still makes an intermittent contact somehow. But again, if I just press the gas pedal a 1/4" down, the “misfire” disappears.

I guess I’ll stress again the bad injector issue to the mechanic.
I’ll change the wires and plugs with Honda originals today and let you guys know.



the last time I changed the fuel, is never

Youch! Just do it whether that helps anything about this problem or not.

A wintertime drop of about 10% in mpg is pretty normal.

I have just replaced the aftermarket wires and plugs with Honda originals and the car doesn’t sputter anymore. I am not holding my breath though…it could do it again in a few days. I hope is not the case.

With Honda at least it’s best to stick with OEM ignition parts:

I once used the cheapies from Advance on a Ford - never again. The Motorcrafts just aren’t that much more $$