I thought that after the engine swap the problems with my partner’s Prizm would be over.

Since then however it has been throwing code p0125, which in toyota is oxygen-sensor related and means the engine never goes into closed-loop operation. The oxygen sensor is on order and should be here tomorrow or Sat.

However since Monday it has been throwing code P0304, and the #4 coil has failed twice(once on tues, I put in a spare coil, and that has since failed).

I found one passing reference that if the engine doesn’t go into closed loop operation it stays in “start” mode and provides extra power to the coils, which may be causing the coil problem. I’m hoping this is the case, because the O2 sensor will solve my problems, but am looking for any other thoughts/ideas as I’m reaching the end of my wits with this thing.