Hi,
If too far advanced, the ignition timing can cause a slower, odd crank. What happens is each cylinder ignites the fuel too early forcing the pistons in the opposite direction. However, the distributor is located in a fixed, non-adjustable position on this truck.
I realize the starter has been replaced, but have you had the battery load tested? Most parts stores will do it free of charge.
Also, a poor battery connection or ground connection will create excessive resistance, and the starter won't get the battery's full power. Here is where I would recommend starting. Check to make sure the battery terminals are both clean and tight. Inspect the battery cables to make sure they are still in good condition. If all appears okay, follow the ground wire from the battery to where it connects to the engine and check to see if it is corroded, loose, or has a poor connection. It would be a good idea to disconnect the battery, clean the terminals and while the battery is disconnected, remove the negative cable from the engine so you can clean the connection.
Here is a link you may find helpful when checking the battery:
https://www.2carpros.com/articles/everything-goes-dead-when-engine-is-cranked
Let me know what you find.
Take care,
Joe
Friday, March 21st, 2025 AT 7:54 PM