automotive

Hello, I have a question I have a 22' JL 2 door V6 8 speed Automatic, and I recently did a lift kit of 3" and 33" tires. I noticed that the jeep is not changing gears how it should from 4 to 5 my RPMs go to 3.5 and it will not go into 8th gear. I wanted to know if a tazer like a Z Automotive...