Join Date: Feb 2003
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SO here we go.... '86 Sammy, engine is stock except for chevy alt., vent tube and custom snorkle with all vent lines plumbed into it. 2" exhaust with a fairly fresh cat. (4 years old). Went to get emissions done yesterday, and I failed. I don't just mean failed a little, it bombed. I'm usually pretty smug when the operator exclaims "that thing will never pass!" as it always has in the past, by a large margin. Not this time. High CO on the low speed test. Mechanic says "looks like a bad O2 sensor to me". Sooo, off to the store for an O2 sensor and another set of plugs (since I hadn't changed them in years). Gap on old plugs was almost .065!!!!! Gapped new plugs at .031 and put in new O2 sensor. Retest this morning. Worse results this time around!!! CO on the high speed test climbed from a passing 02.87 to a failing 06.21, low speed decreased from a failing 06.23 to a stil failing 05.46. What the heck?? Mechanic sez.. "Looks like she's running rich to me". Really? Ya think so?
So, I'm looking for advice. My current course of action is this: Check all vaccuum hoses for leaks, check the EGR valve, check the timing, inspect the carb. for any obvious problems (seems like I remember you can't manually adjust the mixture, right?), and beyond that... I dunno....