I`m trying to diagnose codes P0171 & P0174. My actron scanner reads the fuel pressure @ 55 PSI on my 2003 XKR. Is this too low a pressure?

 

55psi in not low pressure for your car. I took the time necessary to see what year and engine we are talking about 2003 xkr. Please see that you update your signature so you get the best help. The p0171 & 174 are could be a number of things and the most common ones are intake leaks & MAFS problems. See if this helps http://www.jagrepair.com/images/Auto...otos/P0171.pdf