I have a 95 5.0L Chevy truck. It acts the exact same way. I have changed the plugs, wires, dist. cap, and rotor, even replaced the fuel filter. The # 1 plug corroded after 4-5 000 miles. I am thinking valves? What do you guys think? I should say my truck has 175,000 miles on it , all from pulling a tandem axle landscaping trailer or plowing snow everyday of it's life.