NA Miata Throttle Body / Throttle Body Gasket Replacement

This guide will walk you through the process of NA Miata throttle body replacement.

If your Miata is not idling correctly, a dirty throttle body could be the culprit. It could also be a gummed-up idle air control valve (IAC). The IAC is bolted to the bottom of the throttle body on the NA Miata. So you need to remove the throttle body if you want to clean your IAC.

Regardless of whether you or replacing your throttle body, replacing your throttle body gasket, cleaning your IAC, or simply removing the throttle body as part of a basic maintenance service, the same steps in this guide will apply.

Tools Required:

Screwdriver
Needle-nose and hose clamp pliers
Ratchet and 12 mm socket
Catch pan for coolant

Parts Required:

Instructions:

Start by removing the plastic intake crossover tube. This is done by loosening two hose clamps – one on the throttle body and one on the mass-air flow sensor. Then disconnect two vacuum hoses – one running over to the valve cover and the other underneath the crossover tube.

2. Clear up some additional space around the throttle body by fully removing this vacuum hose that was connected to the plastic intake tube.

3. Turn the throttle body “clockwise” to create some slack in the cable, then slide the cable stopper over to the left to disconnect it.

4. Disconnect the two hoses on the idle air control valve. Warning: these are coolant hoses! Have a catch pan underneath the vehicle to catch the coolant.

It can be very tedious to disconnect these hoses. You will have very limited access, especially if the hose clamps are in an awkward position. An assortment of angled needle-nose pliers can be helpful in order to get the clamps loose. In addition, removing the upper radiator hose can help give you some more space to work in.

5. Remove the 4 12mm fasteners that attach the throttle body to the intake manifold. The top two fasteners are nuts and the bottom two are longer bolts. These only go together one way, so do not stress about mixing them up.

6. Finally, you can wiggle the throttle body off of the intake manifold. Sometimes it can be very stuck in place and you will need to give it a few “love taps” with a rubber mallet.

Make sure you scrape the old gasket and clean off the mating surface before re-installing the throttle body.

We hope that this guide has been helpful in walking you through the process of NA Miata throttle body replacement. Check out our other NA Miata DIY guides here. For more tips and tricks to keep you Miata running smoothly follow us on social media.