I have a 2002 v6 mustang and when it's cold outside or frost it's nearly impossible to get it cranked. It just turns over and over without cranking. It's like it's not getting fuel to the engine. And when I'm driving at speed and suddenly slow down or just gradually slow down when in neutral the rpm's drop way low and even dies completely, and I have to re start it. Iv changed the fuel filter and tested the fuel pump at 2 mechanic shops and they all say the fuel pressure is fine. No one has been able to fix it. They just give it back and say they don't know what's wrong. Can someone help?