90 TR failed smog with CO% at 25mph

California 90 Testarossa measured .70 on the CO% when .56 is the max allowed at the 25 mph test. The 15 Mph just barely passed.
Tried the chemical at kragens that "guaranteed to pass smog". Still did not pass.
Any suggestions what could be the cause? Car only has 45K on it.

Any insight would be appreciated.

 

Could be almost anything. A TR in good tune blows almost zero-zero in both tests.

I just ran a 90 TR through a few weeks ago. The numbers were so low the inspector was laughing. He said Sacramento will probably think he clean piped it.

.7 is not that far from what it is supposed to be without cats. A good measurement before the cat can be used for diagnostic purposes but a downstream number is really only good for guesswork.

 

8 years ago the stock exhaust was exchanged with a tuned aftermarket system and passed smog without any problem. This is the first time that I am having a problem passing. It does not look like any cats are on this machine. How could it have passed three times is a good question.

 

Check your smog sheets. The specs are continuously being tightened.