The aFe Silver Bullet Throttle Body Spacer (MPN 46-38001) is a bolt-on intake spacer for the 3.4L V6 in Toyota Tacoma and 4Runner trucks, installed between the intake manifold and the throttle body. Owners on user forums are split on what it delivers. One Tacoma thread opens by noting that most people say these spacers are a hoax, while the same owner reports that they claim to improve throttle response and improve air/fuel mixture resulting in slight gains in fuel economy. That makes this a low-cost, modest-expectation upgrade rather than a proven power adder, so confirm any gain figures with the manufacturer before quoting them. Searches for 3.4L V6 Tacoma throttle body spacer, 99-04 Tacoma intake spacer, and 4Runner 3.4L throttle response mod should lead to this part.
Installation is a straightforward intake-side job. The manufacturer's install sheet for a sibling Silver Bullet spacer (46-38002, a 4.0L application) calls for installing the spacer with its AIR IN engraving facing the throttle body, along with a gasket. Expect to remove the air cleaner assembly, disconnect the throttle body harness, and reinstall the throttle body using the longer bolts and washers supplied, which the same sheet tightens to 10 Nm (89 lb/in). Confirm these steps against the 46-38001 sheet, since the sibling sheet covers a different engine.
Because the manufacturer's install sheet for this spacer family describes a procedure that begins with removing the engine cover, the air inlet tube, and the air cleaner assembly, plan for an intake-off job that is manageable for a home mechanic with basic hand tools. The most important detail is spacer orientation: the air-in side must face the throttle body. Owners on user forums also report that the spacer kit uses longer bolts to clamp the throttle body through the spacer, so keep the supplied hardware together and do not substitute shorter fasteners. Check the 46-38001 install sheet for the exact 3.4L torque values and sequence before you begin.
