To update, the new pump arrived today so I called the shop up. I was informed that they went to move the truck and it started right up. So the question remains. Pump, or not the pump? It seemed dead last week when we had it towed there. Wouldn't start up again. The pump wasn't making any noise whatsoever when turning the key. Now it started right up? I still think there may be something else going on, or contributing to it. This is sounding similar to your story Toby. I forgot to ask if he jumped the pump/ checked the oil pressure switch but I'm supposed to talk to him again tomorrow.

 

It's important to find out if the mechanic tried to jumper the pump and/or checked the oil pressure switch. If he checked the pump with a jumper to the test port then the problem could be the oil pressure switch since the test lead is after the oil pressure switch. Either way that's a very important piece of troubleshooting information.

Good luck!

 

He checked both and they checked out fine. They did diagnostics literally all day on it and couldn't find anything wrong. It starts right up every time now and runs like it did before this happened. So we decided I would take it home and just drive it around town not going very far for the time being to see if it happens again. He was at a loss for what it could possibly be. Lucky for me he didn't charge me anything which is nice. So I'll update it there are any updates. Haha.

 

Before I replaced my pump last month, when the Blazer wouldn't start I would let it sit for about a half hour and then it would start right up. If you're going to drive it around with the intermittent pump problem I would suggest doing the same thing. If it fails to start then wait a half hour and try cranking it again.