[pbs911]

I don't know about Oregon, but dump some techron in the fuel tank and do some spirted driving to blow the gunk out. Also make sure the ingintion system is functioning properly: plugs, wires, cap and the timing is set correctly. When you test the car make sure it is fully warmed up and filled with premium gas.

Prior to the test, take the car to someone with a sniffer and lean out the fuel mixture. Also get the levels your car will be required to pass. Have the fuel misture adjusted to the required levels BEFORE you go to the smog station. As far as I know, there is no visual inspection in Oregon, but I don't know for sure.