I spoke with Manny at MAC. He said there were no current instructions for your kit. They were remaking them. He suggested you call him at (1-800-367-4486) to go over it over the phone. I think this will work for you though:
Here's the install instructs for a 4.0. They have the same stock airbox as the 3.0 so it should be the same. No pics included in the instructions:
Disconnect the battery, then disconnect the wiring harness connected to the Mass air sensor on the intake tube.
Next, loosen the hose clamps holding the intake elbow in place at the throttle body and the air box. Remove the hose connected to the intake elbow and remove elbow from air box.
Pull up on airbox/filter assembly until it comes loose from the grommets holding it underneath. Once unit is removed, make sure rubber grommets are put back in the truck. These will be used to hold the bracket and filter in place.
Remove Mass air sensor tube from stock air box by removing four bolts.
Start installing system:
Connect rubber adapter to Throttle body and Air tube.
Put aluminum pins on plate and tighten down down screws through the top.
Fasten Plate by sliding the bracket into the two grommets with filter attachment facing fender. Mount mass air sensor to other side using the four bolts and nuts supplied in kit.
Attach Mass air sensor to the rubber adapter and the tube using the clamps. Tighten down clamps and reconnect wiring harness and sensor9s) in the hole provided in the tube.
reconnect the battery, start the truck and check for idle fluctuation. if you experience idle problems, check for leaks around clamps and sensor. DO NOT OVERTIGHTEN CLAMPS.
2004 Ford Ranger Sonic Blue 4dr 4x4 4.0 Manual