This is a followup to a previous post. Short version ... Cranks fine, seems like no fire, fuel pressure good then it'll start nd idle perfect for about 30 seconds. 1st hint is a single miss,followed by a double miss approx 5 seconds later, then multiple miss within 3 seconds till it quits. Then lots of cranking before it'll restart if at all. Let it sit for a day and it will do it all over again. All without any codes or lights. Having checked all connections & grounds I bought the Volvo green Motronic 4.4 manual and the wiring diagram. Very informative. I checked every component in the system at least once. All check good individually, eventually. If I would get a bad voltage reading or out of range ohm reading I'd drop to the next step to isolate and it would always check good. Finally in desperation I began disconnecting individual components prior to starting, that, if the ECM doesn't see a signal from it will still operate from a default value. The IAC, AMM, TPS,accelerometer,and purge valve, all gave MIL lights & codes when disconnected. When I disconnected the cam position sensor it would not start at all (contrary to the manual). The ECM is supposed to fire twice per revolution in that condition as it doesn't know what point on the stroke the piston is at. When both O2 sensors were disconnected it ran the longest it has prior to starting the miss syndrome. When it finally died I still didn't have a code or a MIL light. I'm leaning towards a bad ECM. Anyone else with a guess,wisdom,experience?