craigslistmiata

I'm looking for advice regarding a crank but no start situation after an engine install. Here are the facts:

-2005 GTO. Bought it running and driving fine. Engine failed due to oil starvation most likely.
-I pulled the engine and had it professionally rebuilt at a machine shop with a conservative comp cam
-Engine installed with kooks catted, 3/4 headers.
-On the first start, it fired right up, got up to temperature, and ran smoothly for several minutes.
-Engine suddenly died as if the battery were disconnected or the ignition key was turned off
-Checked battery connection and voltage. All appears good.
-Attempted to restart. Cranks but start. No spark.
-Engine reads codes P0335 (crankshaft position sensor) and P2138 (accelerator/throttle position sensor)
-No visible issues with either sensors or connectors

Any tips or suggestions before I start tearing into this? Anyone face a similar situation? Thanks!