Bud M
12-21-2005, 03:49 PM
I have a Jeep Cherokee in the shop that won't pass smog because the nox is too high. They have fixed an intake leak and replaced the cat. They tell me that the cylinder pressures are on the high side of spec at 175 psi and as a result the nox is too high to pass. I have already looked into finding a thicker head gasket to lower compression but there doesn't appear to be one available. Can I lower the nox by richening the mixture with an AFPR?