Hey Scotty
I have a 1987 Ford pickup with the straight six EFI and four speed manual. It starts right up when it’s cold, and after driving around town a bit. However, if I drive it 45 minutes down the freeway, the starter sounds weak and it barely cranks over when it’s time to head back. I’m afraid it’s gonna leave me stranded one day. What could be the issue? Thanks in advance.
The starter, battery, or both may be on their way out, affected by the heat. You'll want to check everything - battery, battery terminals, alternator, and cables. Almost anything could be wrong on a 35-year-old vehicle. (I recently had the same kind of problem on an old Rambler and it turned out to be the battery.)
The way you can troubleshoot this is by checking for voltage drop when it's hot.
Simple enough.
Grab a multimeter and check for sufficient battery voltage at the battery terminals while cranking the engine.
Then check for that same voltage at the Starter while cranking the engine.
It shouldn't be more than a couple 10ths of a volt lower at the starter.
If it is, then it's a battery wiring/connection issue or maybe the starter solenoid on the firewall is acting up.
If it isn't, you need a starter.
