For a long time I was baffled by a hot restart problem in my 93 245. If the car was restarted 30 to 45 minutes after it had been running and fully warmed up, it would barely run - like it was starving for fuel. This would last for maybe 10 seconds, then the rpms would suddenly jump up and the engine would run normally. If the car was restarted inside or outside of this window, no problems. I checked everything: pumps, regulator, lines, injectors, AMM, IAC, TPS, ECT (my prime suspect). Everything except the ECU. The ECU was given to me by a local shop that fried the fuel pump circuit in my original 951, then covered their tracks by grounding the circuit so the pump would run whenever the key was on, and not telling me. When I saw what they had done, they admitted it and then mailed me the replacement ECU, which was a rebuilt (by Python) 561 that supposedly was brought up to 951 specs. Last week, I picked up a 951 ECU from the pick-and-pull and what do you know, it solved the problem.

Lesson learned: ECUs don't always fail by causing a no start condition. When all else fails, try a replacement. As cheap as they are now, everyone should have a spare.