I don't have any definitive answers, Scott, but here's a couple of thoughts. When you say the EGR appears to be working what are you basing that on? I'm wondering if some of the passages in the intake plenum may be clogged up.

For my '89, when it originally failed smog 4 years ago the replacement of the O2 sensor was enough to let it squeak by. When it failed 2 years ago I had to replace the catalytic converter as well as do the valve stem seals to deal with "visible smoke from the tailpipe". This year I was wondering how it would fail, but it passed with some really good numbers, so the cat replacement seems to be holding up.

That's about the sum total of my smog knowledge -- I know there's some really smart people on here regarding this stuff and hopefully they'll chime in. California sure doesn't make it easy to hang on to our perfectly good older vehicles <img src="/forums/images/graemlins/zombie.gif" alt="" />

Eric W.