99 F150 4X4 WITH 5.4 SERVICE ENGINE LIGHT CAME ON YESTERDAY TOOK TO AUTOZONE THEY CODE P320 MALFUNCTION IN THE ELECTRICAL CIRCUIT FOR THE ENGINE SPEED INPUT ..ANY BODY HAVE ANY IDEA WHAT THAT COULD BE..THANKS!

 

P0320 - Ignition/Distributor Engine Speed Input Circuit Malfunction
Probable - Cause Engine Control Module

It's a problem with the crackshaft position sensor (CKP). The reference here is to engine speed, not vehicle speed. The CKP tells the injectors when to fire.

I'm not sure exactly were it is on the 5.4L, but it should be on the passenger side, front of the engine, with the wiring harness running to the fuel injection wiring harness. Make sure it's still conneted. Bad sensor or loose wiring, most likely.

I've never seen this code come up here before. This is my best effort at the moment.

 

do you think this would make the truck cut off.. that has happened several times thought that was the thief system but not sure..thanks for your help!

 

Yes.

Your engine is not equipped with a distributor. Instead, the CKP reads the position of the crankshaft and tells the injectors to fire at the correct time. When the CKP goes out, it's like advancing or retarding the timing. For all I know, if there is no signal, the injectors may not fire at all.

 

ok thanks alot!