I read about the IAT sensor on KRCs page and decided to try it. I did it on my 94 318 Grand Cherokee. I didn't feel anything really and my MPG sucks more!!! (of course 7" of lift and 10 offroad lights don't help) BUT, I had all that before. I have, for performance/mpg, K&N FIPK, jet chip(no programmer made for that grand), 180* t-stat, bosch platinum +4s, lower resistance plug wires, and I never run the A/C in it. I was curious if anyone else had experienced a lower mpg with that mod? Oh, does anyone have any experience with the Speed Sensor calibrators? I decided to fork out 140 bucks to see if that would help my shifts/mpg/power b/c I read that it messes with fuel when you have larger tires or a different ratio gear(in that with larger tires the vehicle acts as if it is going slower and supposedly pumps more fuel into the cylinders). Confusing I know, as soon as I install the calibrator I will post my observations.