Engine turns over kinda slow?

[bennylava]

Hi all. 87 tbi 350. My truck does something that kinda makes me nervous. About one out of every 4 times you start the truck, the engine turns over very slowly. If you've ever heard a dying battery, you know the sound I'm referring to. Like it's got just enough power to turn the engine over a few times, but not enough to actually start the truck.

But it always eventually starts. There's nothing wrong with the battery, I spent extra money recently and got a high quality AGM battery. Gotta be something going on with the starter itself. But it's new too.

The truck has always done this, except for one time when I borrowed a friend's starter for some troubleshooting. That thing would spin real fast, every single time. Sounded like the engine was really trying to start, and actually wanted to start.

These slow starts make me nervous cause you start thinking the truck isn't going to start. Sometimes it stops turning over completely, and then in 3 seconds it goes ahead and starts the engine. Anyone know what causes this? Cheap rebuilt starters maybe? Or could it be a cable, like it's not getting enough current to the starter?