we changed the ignition coil, the distributor cap and still no spark on the 1996 Ford F150 what else could cause it to loose spark?

 

Is it EEC IV system? Not sure when Ford went to EEC V.

Are there any codes?

Could be the TFI (Thick Film Ignition) module. That stopped my 1986 cold.

 

It could be the module (ICM) on the driver's fender below the hood hinge like JCH mentioned but is most likely to be the PIP (pickup module that does what points used to do) inside the distributor.
Some of the later distributors had a bolted down removable plate under the cap to get at it but a lot of them are pressed on which means removing and disassembling the distributor - not an easy job.
If you end up getting a replacement distributor make sure it has the fully machined gear on the bottom (not the cast gear that has some machining). You have an HO roller cam and you require the fully machined gear.

 

Hi,
Hum...Lets see?

It could be...PIP Sensor, ICM, EEC, EEC relay, EEC relay connector, coil, distributor gear, fuse links, coil connecter, grounds, shorts....

The list goes on and on! (don't ask me how I know this!)

Better to get a Haynes Manual and a VOM and do some testing!!!

http://easyautodiagnostics.com/ford/main-index