I have an 1988 F150 V8 4x4, truck won't start. Gets plenty of fuel, but no spark. Primary and secondary resistance tests for ingintion coil are within spec and distributor cap, rotor, spark plug wires look good. All indications say it is the ignition module is bad. Can it be replaced without taking distributor out? What type of screws hold it in place (hex nut or T20)? Or could it be something else?

 

You should check for any code set first or go ahead and replace the TFI.
You may have to turn the dist enough to get a socket in the holes then retime the engine unless you mark it before moving it so it can be returned to the same location.
The TFI from all the trucks from 85 up even the Ranger and Bronco II should all work.