I have a 1996 mustang gt. I have checked fuel rails injectors regulators and they're all good. I've tried numerous thing I just can't figure it out. When you turn the key to the on position you hear the fuel pump hum but when you crank it it will fire but wont run. It has 10 psi of fuel pressure while cranking. Is that enough? I have checked almost everything and I don't know. Help please