Please Help!!

changed midship fueltank on 91'F-250 5.8l,started up and engine is vibrating like crazy.was running almost 1 year on propane since tank was leaking.changed fuelfilter,checked fuelpressure(45psi).sounds like its not running on all 8.replaced sparkplugs,wires,rotor and cap but still vibrating.
somebody has any ideas?

trash in the system .