I was driving home from work last night and my rpms kept dropping to around 3-4 hundred every now and again while on the gas. Eventually they dropped all the way to zero while on the gas and the truck shut off. At first while trying to crank it, it would turn over but not start. I tried jumping it and nothing. I had an icm go out on my old 1996 Ford F-150 and it seems to be doing the same thing. Now the truck won't turn over all it does is the starter solenoid will click every now and again. It's a 1988 Ford F-250 302 v8. My better has 12.1 V from a volt meter not the dash and my grounds are good. Any help would be greatly appreciated.