After engine reaches around 190* and I accelerate as little as half trottle, it cuts out and the computer sets a code 43. It sounds like either the valves or rocker arms are rattling badly when this happens. It runs fine otherwise. Has anyone had this problem or know what may be causing it? I used a freind's scanner and all of the systems seem to be operating properly.

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86 iroc, tpi, compucam, headers, pace-setter cat-back, stageII chip, afpr, air foil, filters, maf screens removed.