[JhwShark]

Since all Pass except for the HC at low rpm's...
Yes, change oil, plugs may be OK but change can't hurt, and always get car to operating temp for some time before pulling into the SMOG check.

Also, on old cars, rings are worn a bit...so use low octane. It has a low flash point in comparison to higher grades. This means that you will burn more if not all the fuel in the combustion chamber, higher octane burns hotter but takes longer to burn all the fuel...so the logic is you burn it instead of un-burnt going down/out the exhaust. This is what I did when I missed the last test.