2006 f150 5.4 91,679.... Last week my cel comes in.. read the codes.. its a knock sensor bank 2.. I figure ill replace both while I'm there.. so I get the parts.. intake man gaskets knock sensors etc.. and I replace them being careful to label the wires I disconnect and all..i cleaned everything etc.. everything went smooth.. get it all back together and now trick won't start..i get fuel but no spark. I check for codes nothing.. not even the knock sensor code. Motor will spin over just fine and you can smell fuel coming out exhaust. Some knee told me to check crank position sensor.. I replaced it.. still nothing.. no spark.. so I figure it must be something I didn't hook up or a pin got bent or something.. so I literally tear it back down to the knock sensors.. everything is/ was hooked back up right and no bent pins.. What could this issue be?

 

Are you getting 12v to the coils?
Should be similar to my 2003 when the ignition switch is in the RUN position the red wire on all the coils should get 12v.
The other wires at the coils all go back the PCM to be grounded at the appropriate times.
The PCM will look at several inputs - crank position sensor, camshaft position sensor, not sure what else.
Your year I think has a fuel pressure sensor which would be a parameter.

 

I got nothing to the coils... not while key in the run position or while cranking.

 

I don't have a Wiring Diagram for the 2006, but in our 2002 and 2003 the 12v input to the coils comes directly from the ignition switch (RD/LG).
You could try as a test jumping 12v direct from the battery to one of the coil RD/LG leads and see if they fire.
All the RD/LG wires are connected together and go to the ignition switch.
Is everything else working that would come on in RUN or START?
There's a 30A fuse in the line in the Excursion, but not the Exped.

 

Everything else is coming on...i wonder could the new knock sensors be bad and causing this issue?

 

I don't think so.
I'm still assuming the wiring is similar to our 2003 Exped - the RD/LG supplies 12v to the coils when the ignition switch is in RUN and START.
If the 12v is missing the wire needs to be traced back to the Central Junction Box to find out why the 12v is missing.
The RD/LG wire will be in one of the CJB connectors.
The wire goes thru the firewall and to another harness connector near cylinder #4, then to a splice right behind coil #4.
The PCM will ground the return lines, letting current flow thru the primary, open the circuit, causing the field in the coil to collapse, generating a pulse in the secondary, causing an arc in the spark plug.
Without the 12v to the coils nothing will happen.
The knock sensor input is used to adjust the timing to stop knocking.

 

Ok... I'm am idiot.. I kept testing for 12v. With key off.... key on got the 12v on the rd/lg.. cranks.. still no start.

 

Since it was running before it's seems like you're missing something the PCM needs to run.
Just for a test you could try what a friend of mine did who has this same problem with a 2004 5.4L Navi.
While someone is cranking the engine he would tap a wire from one of the coil plugs to ground and release.
It would occasionally fire the plug on a compression stroke and the engine would sputter a little bit.
That implies the control of firing the plugs is not happening since very little else has changed since it was last working.
The PCM needs good grounding to the chassis and block for everything to work properly.
I don't know all the inputs the PCM looks at for fire control, some are crankshaft position sensor, camshaft position sensor, throttle position sensor, fuel pressure.
I think temp and knock sensors are used to adjust length of pulse and timing.