I have a 1997 F150 w/ 4.2 V6 The engine continually spark knocks whether
it is warm or cold. I have replaced the coil and plug wires which didn`t change a thing. Any thoughts. Thanks

 

Try changing the plugs and using mid grade gas. If that doesn't work you could have excessive carbon build up.

 

Yep,as torkum says.If it does not knock with higher octane gas then that means you have excessive carbon build up.If it still knocks just the same it could be a bad anti-knock sensor,which is located on the passengers side of the block.

 

I couldnt help but notice your username and location. Im driving down to Ft. Loramie for Country Concert '07 on July 7th. I cant wait!!