With the known good ones you can download for the Z32 from their site. Should give you all the necessary numbers so you can see what is different about your car that might be able to pinpoint the problem...I've never had this problem before, but I think comparing numbers with the BlaZt with a known good would be one of the things I'd probably do just to help eliminate stuff. So maybe it is as jobambo says! All O2 sensors, especially if it runs OK with them unhooked...