Ok so I have a 2003 f 150 single cab work truck. it is a 2 wheel drive 4.6 l triton v8. The other day I was driving it the other day and it started acting up. The it shut off and now it wont start. I was told it was the crankshaft position sensor... It cranks but wont turn on. It is feeding fuel and the cylenders have pressure. what else can it be?

 

You said acting up need more info. Check engine lite? Any codes? The code scanner is your friend.

 

the crank positioner tells the computer when to squirt fuel to each injector and the coil when to fire to the correct piston. this is a very common failure and it is a start/no start part in this engine. I'd try replacing this first.