I have a 86 Thunderbird. I know its not a Truck but it is a 3.8 engine. Right!?
It wouldn't start in 40 below, okay fair enough. Then it wouldn't even click over. So I replaced the relay, a rebuilt starter(checked it first) and it still wouldn't start. Replaced the cables the battery. Cleaned the wires to the starter and solenoid. Now it wants to start but can't seem to catch properly. What do I do? Help.Please.

 

I was reading some of the old post's and ran across this. Man I hope you are not still waiting for an answer. If you are you have been walking for a long time. I made a post on my 86 Bird once and never got an answer. Maybe its a code of silence or something. I haven't as yet found a forum for T-Birds, but I hope there is one out there somewhere.
I finally found the problem on mine. It was that stupid module on the distributor. When I did static test on it it checked out fine. After replacing darn near everything I finally changed it out in desperation and off it ran, just like new. It would have been nice if I had advice from somebody that had that experience. It would have saved me from buying a new computer and weeks worth of troubleshooting. I pulled apart every wiring harness in that darn thing trying to figure out where everything was connected to. It is to bad they don't have an overall wiring diagram for these cars instead of black box diagrams. Anyway good luck and I hope you solved your problem -Gary