Why is my car idling high

Leaking fuel injectors, leaking fuel pressure regulator(very common), internal engine vacuum leak, misadjusted minimum air rate, basic engine problem worn rings, compression low, timing chain slop, tune up.

Very common result of a faulty Idle Air Control Valve. Just replace the valve, it takes about thirty minutes. Based on what you're doing, you're cheapening on maintenance, and should stop that. What you'd have spent on a mechanic could have saved you the added expenses of parts and a lot of worry... I know how expensive Martinis can be.

Forgot to mention: Beware aftermarket sensors and controls motors. Only use Factory replacement if possible.