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99 Silverado 5.3L Auto..
Hey guys, I took my muffler off to see how it would sound. I was thinking of putting just a straight pipe after the collector. When I drove it it fell on it's face on the top end. It acted like it was leaning out or something. It didn't really make sense to me. It has the stock tune but I have stock manifolds and cats. I didn't think it would affect how it ran. When I put the muffler back on it ran normal.. Any ideas? Robert
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From what I've seen in the past, that is typical. The engine leans out tremendously if you go from a major restrictive muffler to none. The PCM needs retuned for the mod if you're going to remove it completely. You should be able to get away with replacing the stock muffler with a different one that still has some restriction to it. I am not sure how far the stock tune will enrichen the base tune but apparently it's not enough.
