I've got a '99 SLT 4wd with a 5.2, every so often I get a Check Engine Light (CEL) with NO codes. I have checked it with everything from a $75 Actron to a $2000 Snap On code reader, and no codes come up. Everybody that has seen it says it's the first time they've seen it. I can clear the CEL and it will be out for 2 or 3 days before coming back on. Through various forums, I've read that it could be a bad ground on the rear O2 sensor that gives various codes that are inaccurate and possibly that could be my issue. Personally, my first course of action is going to be getting my computer flashed.


FYI: it's been going on for 6 or so months and I'm only doing something about it now because it's coming up on time to get my truck registered and the emission test looks for a CEL regardless of codes. I'm going to be getting the heater core changed next week and figure that would be the best time to get it done..


Anyone have any suggestions?