Neutral Reg

Why suddenly closes after drowning heating and smooth handling. Auto-correct-1stRandom today can not drive-dies85Silverado

85 Silverado 5.0 Auto / SD-Cruise, A / C Gauges (oil, temperature, voltage) P / W & Locks, 4-WD. Truck is like new, reg. maintenance (up undrivable) problem occurred randomly rough ran a short distance, but is slowly becoming more frequent and longer lasting. He always started easily, ran smoothly, but died today in attempts to manage, difficult to restart. In the park / neutral, no problem. It was the Chevrolet dealer twice, suspended and their solution is $ 75.00 spark plugs. I know better their condition was a result run rich, not the cause. The last time he was taken, began and perfect, as usual, but 1500 ft Get choked and died. Disposed of air purifiers, discovery choke fully closed. I started, drew cleaner, safe working as a hot gas engine opened and closed on time and died. Doors sanitation open / close properly. Choke light only after the engine dies. Lost qauges except temp. I see what's wrong "is not the cause! CAN NOT FIND technology. Info. Please help?

lose the power of choice. starter goes wrong, or leaving empty