Replaced 2

Have you checked for diagnostic fault codes. The camshaft position sensor is a more common failure item. They both often become heat-sensitive and work again once they cool down.

Did you have to replace the Engine Computer or was it running okay with the one from the 2.7L.

Absolutely. The Engine Computer wants to know when the engine is rotating, (cranking or running) so it knows when to turn on the automatic shutdown (ASD) relay. It knows that by the pulses it receives from the cam and crank sensors. When it sees those pulses and turns the ASD relay on, that sends current to the ignition coil(s), injectors, fuel pump or pump relay, alternator field, and oxygen sensor heaters.