Your stock air intake can be modified to make your truck sound and feel a lot different. By installing a K&N air filter, removing the lid to the filter box, and removing the void box behind the throttle body you truck will gain horse power and sound a lot meaner. First you will need to remove the upper half of the air box. You will not be using this. Remove the stock air filter. Disconnect the MAF and remove the tube from the TB cap to the filter. Disconnect the vent hose from the TB cap and remove it also. You can see that the TB cap has a square box attached to the rear of it. This is used to make your air intake quieter. It also restricts air flow. Remove the hose clamp, remove the bolt, and pull the box off of the cap. The only thing I could find to cap this hole was a coke bottle but I know with a little more time I could have found something that looked a little better. Using the stock clamp and rubber ring attach the bottle (or whatever you have) to the cap. Place the cap back on the TB and reattach the vent hose. Reattach the air intake hose and reconnect the MAF. While the intake is off you could remove the screen from the MAF. Replace the stock paper filter with the K&N. It has a hose clamp that will hold the filter to the intake and the intake system will stay in place. After this mod our 98 Z71 really picked up some ponies.