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