Kevinmacd

Rotors?? These are coils over plugs excited by an electrical pulse from the ignition control system. No wires no rotor, no caps!

Van1

I'm aware of that. Should have been more clear in my previous post. My point was after chasing the simple stuff with no effect (which is what the OP is doing right now) the cause of my random misfire situation turned out to be more obscure, the DMF which these cars do have.

Macster

Could be MAF (DMF?). Kind of odd that it is the same 2 cylinders each time. I would like to think the MAF being common to all cylinders would affect more cylinders or be a bit random in the cylinders it does affect.

OTOH, maybe the cylinders it does affect are the most sensitive ones in the engine and misfire a bit more readily than the other cylinders? Who knows?

Regardless, not ready to throw a MAF at the behavior just yet. I'll touch base with the tech Monday or early next week at any rate and get his input.

Maybe he'll share with me a "trick" to check MAF function? Something that maybe I can use my Actron 9615 (I looked up the model number!) OBD2 code reader/data viewer to look at.

FWIW, and probably not much: I drove the Turbo to work today and even after sitting a night and a day and a night and with rain off and on over that span of time -- the car parked under a car port though -- no misfires upon cold start.

Van1

DMF = Dual Mass Flywheel. There is a sensor that reads the starter ring gear teeth on the flywheel. Theory is that when the rubber coupling between the two masses breaks down it can lead to erratic movements of the ring gear side causing random misfire CELs. Don't know how much of an issue it is with 996TTs but something to think about.

Macster

Oh, of course: DMF - dual mass flywheel. Totally was not thinking.

Doesn't feel like a DMF problem. Take off is smooth and there is no other sign of any problem with the DMF/clutch system in the car. At 120K miles the transmission was out for an RMS leak and replacement of the RMS and the clutch disc had no measureable wear and the rest of the hardware looked just fine. Tech reused everything upon reassembly other than the needle bearings. He always replaces these when the transmission is out.

But I'll keep the DMF thing in mind.