I have an IO-540 with a Bendix servo and spider. Last Fall my first startup went ok with exception of sudden death to the engine after running about five minutes. I traced all the fuel lines, screens, filters and and found nothing. I did a fuel pressure test on the pump and seemed ok but it came with the engine so I replaced it. I replaced the fuel distributor diaphram as well. EFIS show fuel warning 3 psi. Switched tanks, no joy. Any thoughts?