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Cant pass smog 1994 Trans AM

80 Views 0 Replies 1 Participant Last post by  sc1984
Hello All,

I've tried everything in my power to get this thing to pass smog. Tried sea foam, oil change, 02 sensors, etc. I heard once that my performance spark plugs could be part of the problem. I think they are the NGK55 or something. Its been a while. For the life of me I cant remember the model he recommended. What would be the safest spark plugs for trying to pass smog? Im open to any other suggestions. Preferably not replacing CAT as that will cost $1k

Current readings are:

HC 15 MAX 58 Tested 128 Fail
HC 25 MAX 34 Tested 105 Fail
CO 15 MAX .34 Tested 0.27 Pass
CO 25 MAX .32 Tested 0.17 Pass
NO 15 MAX 483 Tested 193 Pass
NO 25 MAX 494 Tested 128 Pass
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