Hey guys I bought a 2004 S60 R the other month and the second day after I got it the check engine light came on. It said that cylinder 3 was misfiring. I have brought it back to the dealership 4 times now and the light still comes on. The light is not always on though, it will be on for weeks then it will be off for a couple of days then back on again. The have replaced the spark plugs, coils, did compression test, and check the injectors. Still the light comes on. They even took it to Volvo and had the ecu updated. Nothing has worked and the weird thing is the car runs perfectly fine. If the light wasn't on you wouldn't even be able to tell there was a problem with it. Any ideas on what could be going on and should I be worried about this?

 

Maybe swap the injector with another cylinder and see if the code changes.

 

they tried swapping the injectors around too

 

Then I wonder if a valve is borderline burnt.
If there is a new coil and injector only thing left is compression.

 

Has anybody recommended running 44k gas addative to your gas and taking the car on the interstate for a good drive? Its about 26 bucks.

 

No nobody has suggested that. I am actually unfamiliar with the product.

 

The Volvo dealer actually suggested 44k. I've used it and noticed smoother idling.