i have checked fuel filter,its tight,all fuel lines have been checked,im getting fuel at the filter and schrader valve,and it will run fine after eithered,but let sit 10 minutes and no start again,primer pump may push down once but still no start.trust me guys i have had this motor looked at 4 different dealers,2 buddies shops ,and even my peterbilt engine shop,the return rates and megapixles are fine,the only new thing that i havent tried is a new factory gas cap,i have a aftermarket lockable cap on now,it is at another dealership today.supposed to have the best duramax tech in area,GM TECH that was good thinking about fuel cap never crossed my mind,thanks ICEMAN..