[MathanaMcLaren]

I've been thinking about doing this for my Rav4 but I don't know how to and if I even can

[PSIG]

Welcome! It begins with looking at your engine's components to determine what they are and how they are controlled. There are thousands of engine versions, and ways to control them, and yours is specific. For example, is the idle air controlled by a valve? A PWM valve or a stepper valve? Where and how does the ECM receive timing signals - crank and cam wheels, distributor, certain sensor types, etc? Once the components are identified you can check in the Wiki and here for if it can be controlled, and any special considerations in doing that.

Another example is if you require Coil On Plug (COP), or instead a distributor, would hep determine the control and signals, and therefore a more suitable version or add-ons for Speeduino or the many boards available. Note there are some functions that are not native to Speeduino, such as direct injection or electronic throttle body control, etc. It also is not intended for use in emissions-controlled or other regulated applications.

Start your planning sheet, and we look forward to what you find!