My GTV6 is with my mechanic. I was actually just driving it up to him to have the thing given a thorough going-over, as it's been sitting for a while.
However, this was the first time I'd driven it for more than 20 minutes in a stretch. I'd experienced some hesitation under throttle before, which I chalked up to bad plugs (they were in fact done) and timing. Possibly gas. I changed the plugs, drained the gas, checked and rechecked the timing (including advance), and hit the road.
After about 15 miles of driving the car began missing. Then bucking. Then stalling.
I pulled off the highway to a frontage road and got stuck at a light. The car died. After some panicked cranking, it came back to life, grumbling mightily, and would only stay running if I rode the throttle. Then it died again as soon as I lifted to make the U-turn to get to the shop. Then again as I crossed the street to pull in. Then it just wouldn't start at all.
My mechanic, who's an old-school Alfa pro, didn't see anything like a missing vacuum line or spurting gas or oil that would give him concern. It's gotta be internal. He's going to give the fuel delivery system a thorough check, then move to the ignition.
It feels like vapor lock, but in my experience, it takes a good long while for the fuel temp to cool down enough to restart. My car did it almost instantly the first few times it stalled. He thought it was strange that the issue got progressively worse the more I drove it.
It wasn't a particularly hot day - mid 70s. Dry air. The engine temp and oil pressure were all normal (or normal according to the car's stock gauges).
Funnily enough, when he tried to start it to move it into the garage, it fired right up.
Bottom line, this one is probably going to be pretty expensive as the testing and diagnosis is an extensive process. I can't wait to explain it to the wife! It's days like that when I just wish I had a Miata...
Any thoughts, though?