Throttle Body Spacer Kit for 91-06 Jeep TJ, YJ, XJ, MJ Models w/ 2.5L or 4.0L RT Off RoadImprove the performance and fuel economy in any 91 06 Jeep 2. 5L or 4. 0L Engine with an RT Off Road Throttle Body Spacer Kit. The heart of this kit is a 1 inch thick black anodized aluminum spacer that is designed to provide a smoother, faster, and more dense air charge resulting in an increase in horsepower, torque, and fuel economy. Also included in the kit is a gaskets and mounting hardware. This kit works with both factory and aftermarket air