I bought a 87 b2000 2 yrs ago, since then, I put a new engine and carb. Well, I noticed that when I changed the air fliter, it gets black, like carbon building up on it, real quick, can't seem to get 10,000 miles on a air fliter, whats up??? Don't think it's runng rich, or is it, and if it is, how can I adjust the mixture?? Or could it be the air injection system??? HELP!
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clogged cats, bad reed valves.