I have a 1999 dekota sport 5.2, auto. which will not start!!

Truck was having the engine cleaned, but was running. cut out when being parked and will not re-start.

Just spins over without firing? like no fuel reaching injectors! is there a relay or fuse to control the flow?

Could this be an imobilizer problem? conected to the panic alarm (factory fitted). can hear fuel pump start when ignition is engaged, there is fuel in tank.