I thought I'd post this. Who knows, maybe someone else is having the same problem. I have 5 one ton trucks (construction company) and am always having problems smogging them. If it doesn't pass one place, I take it to another and it does. I thought the machines were all screwey, but it turns out the mechanics were entering the wrong GVWR. You'd think a mechanic would know a little more about trucks, but some don't. They were either entering it as a 1/2 ton or entering the curb weight of the vehicle, not the GVWR. I just figured this out today with the mechanic at the smog station. It failed as a 3/4 ton and passed as a 1 ton. The sticker on the edge of the door has the info. If you're missing that (like I was) bring your owners manual, there will be a page which decodes the VIN #, the 4th letter denotes the GVWR. I know most of you guys have 1/2 ton Blazers so this won't really apply, but I thought I'd mention it for the 3/4 and 1 ton guys. I asked the mechanic if I showed him the Dana 60 and 14 Bolt under my Suburban, would he test it as a 1 ton? He said get the sticker on the door of my dually or he'd test it as a 1/2 ton next time!! /forums/images/graemlins/blush.gif Atleast he knows what a Dana 60 and 14 Bolt are. Eric M.