Spark Plug Thread Corrosion

[abscate]

It can. It looks at the crankshaft acceleration after each plug firing to see if it occurs at the right time and magnitude for each plug. That’s how it detects which cylinder misfires and reports P030x where x= cylinder misfiring.

If more than one cylinder is misfiring or if it is a really rough running engine the cylinder assignment isn’t reliable and you have to use brain

The misfire code occurs after some limit of misfires ‘ time algorithm is satisfied, that’s in the engine software known only to Volvo.

[cham]

@abscate Okay great, just making sure I wasn't reading false data. I've tracked it a few days and no misfire counts have showed up except one time right after starting the vehicle it registered 1 count on cylinder 1, but then it quickly went away and auto reset back to 0 for some reason.

[Georgeandkira]

It's a month and a half later.
Did your engine smooth out?

I'm asking because I've had 3 of these non-turbo engines and they all had and got the 3-prong plugs.
There was never a suggestion of problem.

Removing plugs, however, can be helped by dropping a wee bit of oil or WD-40 onto the seat and working the old plug back and fourth so the lube goes down the threads. It prevents the screeching and possible galling.
And PRESTO, the new ones go in smoothly too.

[abscate]

I always use oil or anti seize on steel plugs in Aluminum heads. Just a small wipe.

If you get your three prong plugs from FcP you can replace them every 25-30k for near free and they will always come out easily. If you buy the fancy Ir plugs with the extra 10 HP boost, you’ll spend a weekend getting them out at 100 k miles

Those plugs are designed for new cars to tell the Depreciation Fish that their car is maintenance free for 10 years/100k miles

[EngineeringBloke]

I would think you could induce a misfire by disconnecting a coil wire, starting the car (cos you don't want to disconnect it running due to shock). Reconnect and check the counts. Don't run it for long.

Check engine light will come on but should clear after a short time or a odb2 app reset.

Not sure I am curious enough to try it on my own car.