[d-rossco]

1999 Odyssey 255,000KM
Diagnostic codes PO300B through 306B. Missfire. Engine Check and Traction light are on constantly. Engine light flashes at times. No D4 flaching problems.

Last night a friend of mine was checking out my 1999 Odyssey. What I consider rough idle (in park or drive) from a faulty coil... he thinks is partially caused by an exhaust leak. I took a quick look and could not detect one. (in my driveway, not on a hoist)

Would an exhaust leak be enough to create a missfire diagnostic?
(Codes PO300B - to 306B)

I'm going with a coil replacement DIY tomorrow and wondering if it is worth getting the exhaust checked first.

 

[William Wiles]

Search on the codes. There is a good thread on how to diagnose a bad coil which can cause p0300 to p0306 codes. Exhaust leak is not likely to generate misfire codes.

 

[d-rossco]

Thanks WW. That's what I thought.
A coiling I will go! (may as well do the plugs at the same time)

 

[n2wzb]

My 2003 had a similar set of symptoms and codes. Replaced EGR and plugs, cleared codes. Test drive still ran rough, but misfire code was on just one cylinder. That cylinder (#2) had a bad coil.

The way to check coil function is to disconnect power to each coil momentarily (by pulling the electrical connector free) and listen for a slight drop in RPM. When you disconnect a working coil you will hear the drop in RPM. Then swap that coil to a working cylinder to make sure the problem moves with the coil. In my case the #2 coil was dead, the other 5 were fine.

 

[d-rossco]

Thanks N2WZB
That is a great suggestion.

 

[d-rossco]

Success!
Very easy success. Disconnected Coils one at a time, starting with #1, and listened for a drop in the RPM's. The one that had no drop in RPM's was the bad one. And, of course... #6 was the bad one.

It is quite amazing how much impact one bad coil can have on the Odyssey. Shifting, power door alarms.

Any way, thank you to all who helped me with my 2nd Ody DIY (first was alternator replacement.) This club rocks!
Regards