Changed all fuel filters and blead system. Truck tries to start but won't help

Was diesel engine running OK before changing fuel filters? "Air lock" may still be a issue if truck engine had no problems prior to installing fuel filters. Try bleeding fuel system again. If needed you could remove intake snorkle air tube from air filter and spray a generous amount of WD-40 into snorkle tube while while trying to start engine---as engine runs at about 2,500 RPM for a while, this may help clear any air in fuel injection system. It works for me. Best of luck. FFrank--- P.S. Hope you filled your new filters with fuel prior to installing them. This makes bleeding much easer.