I'm dealing with a nearly identical issue. I'm needing to get my 02 TJ inspected and because I'm in Houston, cant bypass the CEL issue. I haven't tried a fix yet because I just now narrowed down the issue to a temp. thing. Temp warms up on my gauge as it should so no sensor issue that I can figure; code says engine stays cold too long. which is total crap. My mechanic (this seemed weird to me) suggested I turn the thermostat 180 degrees and it should fix the problem. Given his previous credibility with me on my annoying jeep fixes, he does know what he's talking about, but has anyone else ever heard of this? Am I just the idiot who doesn't see how this would affect anything?