took the Z out, odd rough idle, that was new, start down the street, can't hold idle stalls out finally get it started and nurse it home. Pull the plugs super carbon fouled, cleaned them, try starting again very hard to start, would not idle then dies.
fuel pressure check, 36 psi during cranking, so at least the FPR and fuel supply/returns are providing the correct static pressure.
Spark looks good and strong.
thinking it maybe a stuck open cold start, I remove it to see if it fires (should not its hot) it does not but the car runs fine with a massive air leak at the cold start hole. plug it up and the engine dies. So clearly its running rich. The only other diagnostic I run is the water temp sender. It test ok about 360ohms (hot engine).
Decide to cut to the chase, swap in a spare ECU, starts right up. runs fine. So the plan is to open the old one up and look for any obvious looking failed parts. I sure am glad I had that spare ECU...