i have a k2500 with a 350 that suddenly lost all power on highway,would not idle acted like it lost 3 cylinders it barely made it home, anyway the gas in it is a year old and has basiclly sat all year,,,,i am thinking maybe the old gas fouled out the plugs???the odd thing is it was all the sudden,one minute running fine,next minute its acting like half the plug wires fell off...its does have 120k on the original engine that i have never had to do anything to it,, is it possible that the timing chain slipped?

anyone have any ideas on what it could be??

 

its the fuel pump,its at 4 psi,,overlooked to obvious