Sounds lame but are you sure that all the wires are fully seated in the
connectors and on the spark plugs?
Perhaps you need to reexamine the intake air ducting between the mass
air flow meter on the engine's right and the actual intake, including
the tightness of the clamp between the plastic duct and the metal air
intake on the engine's left side. (A long screw driver is needed to
tighten that clamp.)