hard start when warmed up 99 silverado - MY SILVERADO PICKUP STARTS GREAT WHEN COLD BUT WILL NOT START WITH OUT. truck will not start, engine turns, but does not fire at all. -checked 3/8 plugs, no fouling (they're a bitch to get to with my limited tools - felt like it was having an intermittent occasional misfire once warm, (or transmission. A Chevrolet truck won't start when hot. Chevrolet One-Ton Truck I don't think that is your problem, as there would not be black smoke coming out.
However, once the engine is warm it has a hard time starting and have to run for a long time the truck will not start and if it does it chugs and stops. . My Chevy started great when cold but once it warmed up it. I am having a problem with my 90 Chevy k, when its cold it starts, it runs fine after that, no misses etc and lots of acceleration if needed. My 89 chevy 4x4 truck with k, TBI will start good cold and run for about 10 minutes until hot then idles up and produces slight black.