2003 chevy tahoe z71 4x4.....no engine code lights....whether the vehicle is cold or warmed up it takes two turns of the key to start. I turn the key to crank it the first time and it just turns over and then as soon as I bump the key again it cranks right up. I thought it may be the pressure regulator valve after researching but when i pulled the hose off no fuel came out...any suggestions on what to check?