I let my dad borrow my car for the day cause he was takin my mom into San Francisco. He said he came to a light to make a right hand turn and the car lurched forward and died. So, he thought that he had accidentally let the clutch out while it was still in gear. Tried to start the car back up and it wouldnt turn over all the way.
He had to get it towed to the nearest dealership and they ran an engine diagnostic on it, the ECU failed. Has this ever happend to anybody elses Z? The car is still under warranty, thank god, but I still found it strange the ECU would just go out like that for no reason.

 

ECU's have been known to "fry" - happened to me on my '97 Nissan 4WD pickup. The truck would turn over just fine, but no spark to start. Nissan dealer showed me the ECU after removing and it had a burn mark on the outside casing where it fried & you could smell the burn up close. Said the distributor shot a spark straight thru to the ECU & fried it. Happened right after something similar to your dad - I was backing up and the truck stalled after a small lurch & stalled. They had to replace both the ECU and a fuse block that shorted out. Thank God for warranty!