Hey guys new to the forum and have a big problem. Ive had my accord for about a year now and just started having problems with misfiring/backfiring. My car struggles to get to 45mph. But above 3000rpm it wont misfire as bad it still will misfire. I thought that it was the pump starving the engine for fuel but that wasnt it. And I did a tune up about 6months ago. So now Im thinkin it might be an ignition problem like a bad coil or some thing. I dont see or hear any vacuum leaks so Im not sure as to what it might be. Someone please help this car is great to drive and I want to make it last. Thanks

 

Open the hood and look at the engine at night in the dark. If you see a light show then you need new spark plug wires. That would be my first diagnostics given your problems. Let me know what you find and read the posting rules pertaining to your signature before you post anything more. If you don't have a signature, most of the better techs and members of this forum will ignore your posts.

 

I just replaced the plug,wires, cap/rotor, fuel filter about 6 months ago so I doubt its that. Thanks for letting me know about the whole sig. thing

 

You could have a bad plug or wire. I would remove and inspect/gap all the spark plugs and do the wire check suggested. Inspect your distributor cap and rotor for cracks even though they are new. Ignition cross-fire (spark jumping to incorrect cylinder) is most likely reason for a backfire. Also check the engine base timing.

If none of the above, a weak coil might cause misfiring. Not sure if weak coil would cause backfiring.

Excessive fuel supply might cause both misfiring and backfiring. Check fuel pressure regulator vacuum reference line for a strong fuel smell. If yes, then regulator diaphragm has ruptured allowing raw fuel to be pulled into the intake through the vaucum line.

good luck

 

Ill check all the plugs and see what the condition of them are. And Ill take the cap off on my lunch break at work to see what it looks like.