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1987 Toyota Corolla LE 5 Speed Manual Transmission failed the smog test.

We recently purchased a used car in CA and the previous owner gave us a smog test report that was performed in March 2010. It failed the smog test we needed to tranfer ownership. The car was only driven 4500 miles between the two tests. The HC went from 43 (@15 mph) to 288 (@15 mph), and 28 (@25 mph) to 161 (@25 mph). The NO went from 174 (@15 mph) to 1636 (@15 mph), and 208 (@25 mph) to 1157 (@25 mph). What are some of the possible reasons for the drastic change in readings?
Answer:

This is a tough one. It's almost as if the results are from two different cars. It's very difficult to say what would cause readings this high. Without knowing what amount of CO (Carbon Monoxide) your Toyota produced, I will assume your Toyota has a lean fuel mixture problem. It's the one problem I can think of which would produce high HC due to a lean misfire in one or more cylinders, and at the same time cause high NOx. I have to recommend you get a hands-on diagnosis from a certified smog check repair station to find out exactly what's causing your Toyota's smog failure. Once they find out the real problem, you and the smog station will be able to determine whether the fault/s could have occurred within 4500 miles. If it's determined the problem has been there for sometime, you may want to get back in touch with the seller and find some recourse... By law they are supposed to give you a passing and unexpired smog check certificate at the time of sale. posted by SmogTips Support

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