Kind of a strange one that's driving me crazy. Truck starts right up cold. I can drive it all day as long as I don't turn it off. If I turn it off it will not restart--will crank but no spark from coil. I have changed the coil, changed the distributor (twice because I thought the first one must be faulty). I also added a ballast resistor thinking that might be a solution. (I don't believe my truck ever had a ballast resistor but I see the part on RockAuto). No improvement. Problem definitely seems to be heat related--starts right up when it is cold, might restart if I turn it off and right back on, def won't restart if it "heat soaks" for 10+ minutes. Any help would be most appreciated.