I've been having a random starting issue for about a month now.
1st start of the day, middle of the day, end of the day doesn't matter if the truck is hot or cold.
Typically only once a day or every couple days.
Plenty of power everything works but the starter relay would click when trying to start the truck. Flip the key back do a 3 count and typically it would fire right up which made this very difficult to diagnose.
Once or twice on the 2nd try when the problem would exist it would start to crank and then slow and stop. I was leaning more toward a battery so I replaced it, cleaned both battery cables and the ground to the motor.
And after 3 days original problem resurfaced.
So I was going to do the voltage drop test when I discovered this little guy. Power wire for the starter relay:
It's green and nasty like it came out of the titanic. So I soldered a new wire in, cleaned up the contacts on the relay put it back together. She fires right up. I also cleaned up the contacts on the starter.
Voltage drop after:
Neg side = .4
positive = .1
I know I should have done the voltage drop test before but I didn't.
10 starts in the driveway and no issues. The real test will be when I'm on the job site 50 miles from home.
If you think I'm missing something please post or if I'm doing something dumb.
Otherwise, hopefully this helps someone because so many people are quick to say it's definitely something when it reality you need to Check your stuff. Buy a service manual if you don't have one because it has paid for itself within a few months already.