Just bought a*2000*ram*2500*and it seems like it has a few issues i need to address. First, air only blows from defrost (front of dash by windshield) and i read that it's caused by vacuum leak. I do have 4x4 however. Whats the best way to diagnose? Just let it run and look for leaks?

Also, i have a*edge juice programmer*that reads my fuel pressure at 33-34. It has a*FASS 150*fuel system on it but i do need to change my fuel filter. From what i gather it should read ~18 at idle and ~12 under load? Hoping my sending unit is not gone...or worse my pump

And something that scared me happened today... I have had it for 3 days and it has ran fine. Today i go to start it and the Edges alert pops up with Fuel Pressure Alert 0 psi. Turned it off. Turned it on again and it read that same thing with*only*3*psi. Turned it off then turned it on again and it popped up again but i let it run for like 30 seconds and the fuel pressure slowly started to rise again until it reached 33 psi. Hoping its just a dirty filter..... filter is being ordered