So just to be clear, from what I remember is that the return line is where the FPR is connected. The line that feeds the fuel rail is the one with the check valve. Correct? The flow of fuel according to this pic of your engine is from left to right. Thanks! I replaced the plugs, cap and rotor, but still experience starting issues. I have a really good check valve ready to so I figured tomorrow would be a good day to install it