Check the timing belt.
The 3.5 L timing belt drives the water pump and these are great for the pumps going out and taking out the belt.Even if the pump is ok,still the timing belt could be bad.
If thats the case,always replace the water pump and timing belt together.
If the camshafts arent turning,the cam sensor will not send a signal to the PCM to fire the coils and the Automatic Shutdown Relay (ASR )will shut down the Coil,Injectors,alternator,fuel pump relay,heated 02 sensors within like 1-2 seconds of cranking.
Take a couple bolts out of the front cover on one side,loosen enough of the rest to slightly pull the cover open at the top and have someone crank it while you look in to see if the cams are turning.You can peek in there too and can see if the belt is shredded.
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