FORUM RULES UPDATED - The forum rules have been updated to continue to provide a friendly and safe environment for our member community. Please take a moment to review the updated rules and our terms of use and privacy policy. Click here for Forum Rules which has links to the 'terms of use' and 'privacy policy'.
Remember to get the pressure when it's 'stumbling' not when its running ok....but I bet its the same problem i had with two of thes 300 HPDI engines....when running hard the vacuum rises above 4.5 inches of mercury....due to the length/diameter of the fuel hose....maybe one engine has a longer...