I just smogged my k5 cause I have to register in Cali now. It passed but barely. I live in an enhanced county so I have to do the dyno testing. here are the results. timing 0 tdc 15 mph / rpm-1460, hc-118, co-.28%, no-808 max / 120-.74%-1045 25 mph / rpm-1408, hc-74, co-.31%, no-595 max / 92-0.93%-1040 The hc and no at 15 mph are what concern me they are really close to the limit. I need and oil change could this be causing the high readings or possibly my cat is going bad. I drove the truck for about 15 min before I went to the test station and only sat for maybe 2 min waiting to go in. I have 2 years before I have to do it again so it is not a big concern right now. Oh yeah the engine has 179, 815 miles on it could that be why hc and no are high. Thanks.