u/JackStraw44

Guys, I’m at a bit of a loss. Car is a 2001 330ci 5-speed. Just did a cooling system refresh (radiator, water pump, thermostat, and hoses), bled the system, then took it for a 20 minute drive and everything ran great. Came home, opened the bleeder screw to let any last air out, closed it back up and now the car flat out won’t run. It’ll start, run really rough, then die a few seconds later.

I’ve done the obvious stuff like rebleeding the coolant system, checking for vacuum leaks, etc, but nothing has fixed it. Car has no codes. It has to be a vacuum leak, no? But why would it start after just loosening the bleeder screw? Anyone have any suggestions? Thanks in advance!