2001 Blazer won't start sometimes

I've seen a lot of posts on here about Blazers having problems starting, but I think my problem is unique. The Blazer actually belongs to my girlfriend. She had a problem last Fall with it not wanting to start. She said it acted like it was out of gas. BUT... she said when this happened the door locks would go nuts too. They would flip up and down by themselves. I told her I thought it was a grounding problem but a mechanic told her it was the fuel pump. She had the fuel pump changed and it worked for about 6 months. Now the problem is back. Any suggestions???

Mick

Check the grounds, check fuel pressure, basic diagnostics.