Australian Car Repair Issues? Ask an Auto Mechanic for Answers ASAP
I work for Holden.
Your combo might have some moisture in the spark plug tubes.
It may come good after a day or two, how long ago did you wash the engine?
Does it put the engine light on while driving with the misfire?
This is why one has to careful washing engines, something to be wary of.
It would be wise to get a diagnostic check done with Tech2, the DTC that will be set will tell you which path to take for diagnosis. Have you got a Holden dealer nearby for a diagnosis check?
For example, if it has a misfire code, say P0301 cylinder 1 misfire detected, then the coil pack needs to come out for further inspection.
All tailpipes these days are rich because of unleaded, fuel injectors are turned off for cylinders that misfire, so no unburnt fuel exits the tailpipe.
The coil pack is under a plastic trim, it is held in with two T30 Torx bolts.