Still working away on the wagon, just happy to have it running down the road.

However, it has a very noticeable stumble when cold that lasts for 20 or more minutes while being driven.

The car jerks and bucks hard, it's almost as if the engine is cutting out every second or so.

As I drive it the stumble decreases in frequency and force and within 20 minutes or so the stumble is gone. If the car is shutoff and restarted it does not stumble unless parked for 8 hours or so.

There's only a few things I haven't recently replaced or checked the function of; ignition coil and injector seals. Plugs, wires, cap, and rotor are all new.

It seems to me that this is spark related because it cuts out and comes back very quickly and seems to effect all cylinders. I would also expect the fuel system to trip a fault code if there is a problem with it. Primary fuel pump and filter were replaced a few thousand miles ago.

So I'm guessing it's the coil, being body mounted it would take longer for the heat to drive off moisture in the coil. I did check the coil with my DVM per the Bentley manual but seeing as how this is an intermittent problem I'm not confident that a static test will detect the issue.

What do you all think?