Hi All,
I have a 2004 Vectra C, recently it has started to missfire after about 30 minutes of driving.
Codes: P0300 Random Misfire Detected.
When cold it starts easily, runs and idles smooth - although the tacho seems to wander around 8-900 RPM
Once the engine is hot it randomly starts misfiring and seems to be running on 2-3 cylinders, the missfiring is at idle and constant throughout the rev range.
Once the car has cooled completely it runs fine again.
Replaced:
Plugs
Coolant temp sensor
Fuel filter
Air filter
Cleaned:
Throttle body
Where do I go from here?
Any advice appreciated.