Hey guys me again.

I bought a alternator after old one read to much alternator noise,  well now trucks sometimes getting power to pump and sometimes just won't start , fuel lift pump kicks on but once it even attempts to start not turn over , it won't cme on for a second,  not really.familiar but after all I've replaced I'm looking towards ecm telling vp not to start ? Or...

I know that yall may not be able to help but thanks ahead

Because it was new when I drove off lot v I believe running it low the day it died probably sucker all the trash up that was in it , I literally had the truck 1 day off car lot , new lift pump filter and all , so when I did change it , I did notice the old one was to clogged , but see yesterday I started vehicle let idle a second and put it in reverse it died down,  oh well it's at mechanics,  he thought it was vp44 so I guess we will see , mine probably just needs to be flushed honestly, but I'm sure whomever gets my core charge will do that