Here are some write-ups and information that I made while working on my 1986 F150 XL 5.0 (302) EFI. 
Much of the info is useful for '80 to about '88 Ford trucks - F150-F350.

OBD I  Self Test and How to Read Check Engine Codes

Dual Fuel Tank Selector Replacement and Fuel System Troubleshooting

Cruise Control and Horn Bar Diagram