I have a 97 TJ with 4.0, 4:10 gears, 33" tires, K&N air filter(stock),5sp., Borla Exhaust with Header. I am experiencing surging/hesitation when giving full throttle lower rpm's (especially 3rd gear on an incline...1300 - 2300rpm's). After you get the rpm's up to upper mid range finally clears up. I have replaced fuel pump, injectors, MAP sensor, Throttle Position Sensor, went from 3:55 to 4:10 gears (suggested from Rock-It), comlete tune up with champion plugs. Better performance overall BUT did not correct surging/hesitation. Tailpipe burns black and feels seems rich. One of the Jeep dealers suggested that the ECM may need to be re-programmed but was not sure if the technical bulletins covered the exact problem that I have(re-program would address my symptums . I have read about the computer chips (JET, Hypertech,etc.....sounds like some of the same things that I am experiencing. Has anyone had this problem? Any feedback on the chips?