how do you go about "tuning" your RX7?
like how do you check the air/fuel ratio?
I want my car to run perfectally and fast but I know chances are I have a vacuum leak which will slow the car down.. is there a computer out there I can hook it up to to see EXACTALLY whats wrong?

 

you can make a tester light...by your name i guess that you have a 87?

 

To check the A/F ratio, you need to find somebody with a Wideband O2 sensor with a tailpipe adaptor.

However, "tuning" the car involves a bit more than just checking stuff, you are going to have to install a SAFC or some other type of fuel computer to "tune" the car. With the stock computer system, you really can't adjust your engines parameters without a "piggyback" system.

I see you have an 88TII, lemme tell ya, when i first got mine... even though the previous owner took it to the dealership for EVERYTHING, i found about a dozen small leaks, including a leaky UIM to LIM gasket that weeped under boost (sounded like a steam wistle)

As for the vaccume leaks... the best way to find them is to spray the suspect hose with carb cleaner and wait a second or two... if the engine dies or stumbles directly after a spray, BINGO... the bitch is that the Oil injector vaccume spider is one of the problem children and its down under the intake manifold. Just spray something, wait a few soconds and spray somewhere else (and keep a fire extinguisher handy just in case!!)

If your car still has the original hoses on it... do yourself a favor, tear the intake off down to the lower intake manifold (leave that on) and replace EVERY vacume line with silicone lines and zip tie 'em.

 

for the oil injectors spider vacumm lines, how do you spray them while the engine is running?

 

Depending on the mileage, it migt just simpler to replace all vacuum lines. Its a afternoon job, easy to do (if you remove one, replace one) and your car will run better. To get the injector lines you have to spray kind of blind. If you do have a leak, your ripping the manifold off to fix, so just do all.