I went to smog my 91 qamigo the other day. as usual it failed. It was running rich. The percentage allowable is 1.2. I was running around 7.6. I did the usual fix. I changed the O2 sensor. This time it did not work. It did go down. It went from 7.6 to 4.5. Usually this quick change out brings it down to 0.61 or close to that. I am still running rich, any ideas? I really need to smog this darn thing.