yodaforce
+1y
If the alternator is good, then when you yank the positive cable off of the battery the truck will still run off of the alternator. Another test is to put a meter on the battery while the truck is running. If the voltage steadily drops then it is running off of the battery. If it stays constant, then the alternator is charging properly.
The electric choke should have 12v when the ignition is on. Otherwise, it should not have anything to do with killing the engine. All it is is a heating coil that stays contracted until it is enegized, which heats it up and expands the coil, thus opening the choke plate as the engine runs.
I have had starters and alternators checked at shops and at the local parts stores. Not always reliable. My wife was out of town one time, broke down after going into McDonalds, right next door to Advance Autoparts. I told her to go over and have them try to help her out. They do, and then they sell her a $100 battery. She gets home, I check it out, and when I asked about the greasy hand prints on the engine fuse box, she says they "checked them". I look inside and there is a brand new fuse! The one that starts the car! Pretty good. They sell her a battery and slip in a one dollar fuse (which was the real problem).
My advise is if there is any doubt about your alt., go buy one. Keep it clean (wear gloves if neccesary), install it, try it out, and if your problem persist, take it back and get a refund. Otherwise, poke and prod for a week or so, until you realize that the alternator IS the problem.