That's odd, you should not be seeing that happen, and if it did you would be in a lot of trouble. Are you sure they knew what they were doing? You don't have a wideband in your Cobra do you? 18+ is like completely lean, no fuel, your car will see a completely lean condition when you shift but will then drop to well under 12 at WOT. It's almost like they have something hooked up backwards lol and rather then going rich it's showing a lean condition. No motor could handle even one pull under any arf close to 18+ I wouldn't think???

Does the car seem to run differently when you get on it?