So I had a 2000 Volvo s70 non-turbo w/ 180k+ miles and the heater core went out which caused the engine to overheat, which in turn blew the head gasket and who knows what other damages occurred. We decided to just swap out the engine instead of going in and trying to replace the head on an engine close to it's end of days (especially after driving it hot and blowing the gasket). Of course, we replaced the heater core.

We came across a good deal on a 2002 Volvo s60 non-turbo engine with only 80k miles on it and decided to go for the swap. After the swap, engine runs fine for the first 10-20 seconds after start-up, but then begins to stall as if it's misfiring. OBDII codes P0328, P0339, P0336 are being read, which when checked refer to the knock sensor and the crank position sensor.

Any ideas on what I can do to fix this problem? If I'm in deep, I'd really appreciate the honesty!