I'm fixing my mother in law's 2000 Pontiac Montana with a 3400 in it. For some reason, if you disconnect the battery, wait a few hours, then reconnect it, it runs perfectly. But the moment you shut the car down, it will crank but not start unless you disconnect, wait, reconnect. I have no idea what would cause that at all. Fuel pump is priming, I'm gonna see what the pressure is tomorrow morning, along with checking to see if spark is present. Figured I'd ask if anyone has ever experienced that before or has any ideas on what could cause it.
