Hi all,

I figured I could help some people out and post my problem with solution after very poor guidance from both mechanics and parts store.

2002 Honda Accord EX, 150K miles V6 engine.

I started it up the other day and it sounded terrible. It was sluggish and I had the Check Engine Light on as well as the TCS light.

I went to the autoparts store to have the codes read and the following popped up:

P1399
P0300
P0306
P0305
P0304
P0303
P0302
P0301

All of my cylinders were misfiring.

-I called a garage and they said bring it in for a diagnosis at $125.
- Stopped at the autoparts store and they said to change my fuel filter and spark plugs.

I pulled all my plugs, and cleaned them and made sure their gap was correct.
I checked my battery voltage
I filled it up with gas

Still had the problem. I purchased a new ignition coil at $50. I swapped the coil on different cylinders. When I swapped out the last ignition coil the car ran great!

Conclusion: One faulty ignition coil can in fact cause multiple misfire codes. Start with the absolute basics first.

Hope this helps someone. I must have read in 4 or 5 different forums that a single ignition coil will not cause multiple misfire codes. False.

 

No problem since then?
I second what he said, I had exact same thing on my 2001 v6 today, I had to swap cylinder 4's, ignition (spark plug) coil, it was the first one misfiring in the normal firing sequence. Let's see if that was the whole issue.

 

There are some threads on here addressing the same problem, where the solution was one bad coil.

One way to find the bad coil is to start the engine and unplug one coil and listen for a change in how the engine runs. Plug the coil back in then move to the next coil. When you unplug one and you hear no difference in the engine, then you likely found the bad coil.

 

Nice post. My first inclination when presented w/ mulitple misfire codes and a Coil-Over-Plug engine, would be to look for something besides a single failed coil that could impact all cylinders. Your post indicates that may be a false trail.

If you're interested in exploring engine diagnostics, the channels by , "reafixesrealfast", "ScannerDanner" and "Schrodingers Box" on youtube have some excellent videos. Some are very advanced, but many are quite useful to the DIY'r. I especially liked the simple explanations by Schrodingers Box on understanding importance of LTFT and STFT when addressing a problem.


good luck