Intermitant Misfire

[Turbo2.2Coupe]

MS2Extra ver3.4.2 V3.0 , Dodge 2.5 Turbo, single Hall pickup dizzy , Modded Hall input circuit for pullup, various CDI boxes/coils
I have had close to 50,000 miles on this MS2extra with no major troubles till now , but this was not initially caused by the Megasquirt as far as I can tell. On a 10*F day I had started the car to thaw-out , after idling for twenty minutes , it just shut-off. I only found a fuse [40amp] for the electric fan had blown. No other parts electric or Megasquirt related appeared to have been affected as the fan circuit is isolated with its own controller and fusebox. I replaced the fuse ,cranked the car , no spark , no D-14 light or light on CDI box. Checked for spark mechanically , everything spec'd as good. Checked all electrical , all spec'd as good , also had switched to spare CDI boxes . Put my spare Ms2 box in , car started right-up. Let it idle, drove it four miles , shut it off . Went to start it two hours later , no fuelpump , no spark , no lights on MS2 at all. Main power relays working , intermitant power from fuelpump relay and ignition relay. Checked first MS2 on stim , no pump or ignition or anything. Orderred parts from DIYAutoTune few weeks ago . Replaced Q2 ,Q19 , checked resistances , traces ,etc,... all seems good , ran on stim - good. Put repaired unit in car and it has ran good about 500 miles then has started intermitant misfire [or is it a shut-off/reset ?]. Datalogs show ign. spikes , TPS spikes , AFR spikes , but nothing consistent [no sync-loss shown] . The car might run good for hours or might misfire every few seconds , varies day-to-day. Only other change was wideband sending unit , had an LSU 4.0 now LSU 4.2 for an LC-1 . Recalibrated and firmware upgrade for the LC-1. Afr has not worked the same since the new sensor. I turned-off Accel and EGO control as with the new sensor the readings were so different the VE's have to be redone. Any input is much appreciated , this 1992 Dodge Shadow is my daily driver, John.