The Wrench Time

• Estimated Time: 45-60 Minutes
• Difficulty: 3/10 - Beginner friendly, basic hand tools needed. Perfect first mod for the 3rd Gen T4R.

Tools You Will Need

• 10mm and 12mm sockets with a 3/8-inch drive ratchet and 6-inch extension
• 10mm wrench (for the battery terminals)
• #2 Phillips screwdriver (preferably JIS to prevent stripping factory hardware)
• Flathead screwdriver or 8mm nut driver (for aftermarket worm-gear clamps)
• Needle-nose pliers (for factory spring clamps on PCV/vacuum lines)
• 3mm or 4mm Allen wrench (typically required for aftermarket MAF hardware)

Phase 1: Removing the Factory Part on your 1999-2004 3.4L 4Runner

1. Disconnect the Battery: Always start by disconnecting the negative battery terminal using a 10mm wrench. This prevents check engine lights and allows the ECU to reset its fuel trims for the new airflow.
2. Unplug the MAF Sensor: Depress the clip on the MAF sensor wiring harness and pull it straight back. Using your #2 Phillips screwdriver, carefully extract the two screws securing the MAF to the airbox. Gently pull the sensor out and set it in a safe, clean location.
3. Disconnect the Vacuum Lines: Use your needle-nose pliers to squeeze the factory spring clamps on the vacuum and breather hoses attached to the intake resonator. Slide the clamps back, then gently twist and pull the hoses off the plastic nipples.
4. Loosen the Throttle Body Clamp: Take your flathead screwdriver or 10mm socket and loosen the factory hose clamp securing the intake tube to the throttle body.
5. Unbolt the Factory Airbox: Use your 10mm socket and 12mm socket with a ratchet to remove the bolts mounting the lower airbox and intake tube brackets to the passenger-side fender apron and engine block. Lift the entire chunky OEM intake assembly out of the engine bay.

Phase 2: Installing the Cold Air Intake for Toyota 4-Runner (1999-2004) 3.4L Engine - Black

1. Prep the Heat Shield: Assemble the provided aftermarket heat shield and drop it into the factory airbox location. Secure it to the OEM fender mounting points using your 10mm socket and the supplied hardware.
2. Install the Silicone Coupler: Slide the new silicone transition coupler onto the throttle body. Slide two aftermarket worm-gear clamps loosely over the coupler. Tighten the throttle body side down snugly using your 8mm nut driver or flathead screwdriver.
3. Transfer the MAF Sensor: Carefully slide your factory MAF sensor into the machined billet MAF pad on your new black intake tube. Secure it using the supplied Allen head bolts and a 3mm or 4mm Allen wrench. Do not overtighten and crack the plastic sensor housing.
4. Route the Tube and Reconnect Lines: Plunge the new intake tube into the air filter inside the heat shield, then slide the opposite end into the throttle body coupler. Align everything for clearance away from the brake lines and radiator hoses, then tighten all remaining hose clamps with your 8mm nut driver. Push the factory breather and vacuum lines onto the new welded aluminum nipples.
5. The ECU Relearn Procedure: Reconnect the MAF sensor harness. Reconnect the negative battery terminal using your 10mm wrench. Start the vehicle. Do not touch the gas pedal for at least 20 seconds. Let the 5VZ-FE idle and allow the ECU to calibrate to the increased volume of dense, cold air. Check for any whistling sounds that might indicate a loose clamp or vacuum leak.

Disclaimer: This is a general guide provided for the 1999-2004 3.4L. Always refer to your factory service manual for exact torque specifications and safety procedures.