take the crank sensor out and clean the mounting surface on the block, reinstall see if that help's
No of cranks used in 6 cylinder engine
THE netural Saftey Switch could B bad .
if it wont crank the the starter is probally out but if it cranks and the motor doesnt turn either the belt is to loose or the engine is locked up
Cranks is the motor turning over, But cranks and won't start means either you no fuel or no spark or both.
If the engine cranks & cranks & cranks before it starts even though it's warmed up already.
does it have a computer, is it correct computer timing may have been moved while swapping.
You need a battery. There's a very small chance it could be something else, but from the symptoms you describe it is more than likely a bad battery.
Check engine compression Check engine timing
No, The compression test is done as the starter cranks the engine
Engine cranks but doesn't start.
An engine which cranks but will not start is not receiving enough fuel or has no spark. A clogged fuel filter or bad spark plugs often cause this problem.