ODB code P305 Cylinder 5 misfire

Padre70 · Post by **Padre70** » 13 Apr 2012, 19:15

I have a 1997 960 with 183,000 mile on it, and has run just fine until last week when I suddenly got a misfire while driving on the freeway. When I stopped for a short time the misfire went away. This has persisted for the last week and is driving me crazy as I have replaced all plugs and ignition coils, had my mechanic check voltages on all coil connectors, compression, exhaust (in case of a bad converter), drive the car for twenty miles with no problems. The next day the problem reoccurred. We are beginning to think we have a ghost in the engine compartment. Also, number five plug is wet when pulled out. Would a hotter plug solve the problem? Any one that has encountered this problem before, I would appreciate any kind of help.

Post by **billofdurham** » 14 Apr 2012, 15:49

Welcome to Matthew's Volvo Site.

I haven't had this problem but, as you have changed the plugs and ignition coils, I would be checking, very carefully, the wiring to #5 coil. There are many recorded instances of the insulation breaking down due to the heat from the engine. As #5 plug is wet when you take it out it is obviously not a fuel problem.

Bill.

Padre70 · Post by **Padre70** » 14 Apr 2012, 16:30

Thanks Bill,
We have pulled the insulation back from #5 cylinder wiring and re-soldered a bad frayed wire, but the problem persists. I am going to wrap the ignition coil with electrical tape and get a hotter plug. Also a friend suggested sparkplug thread gel and top cap gel to help the transmission of electrical current to insure a good spark. I am at the point of re-wiring the cylinder ignition coils if this doesn't work.
Regards, Padre70