Hunting issue

[jondee86]

In the case of a factory ECU and stock engine, the idle quality is actually
very good if the engine is well maintained and tuned to specification. It is
one of the strong points when comparing stock to aftermarket ECU's.

When problems arise it is usually because adjustments have been made to
things that should not be adjusted, and the engine is no longet tuned to spec.
If the throttle stop screw has been messed with, not only does it throw the
TPS setting off, but the blade may not be closing fully, allowing extra air
into the manifold. Looped vacuum hoses can cause permanent high idle.
Messing with the ignition timing because someone said more advance will
make extra power, will raise the idle speed. And anything that changes the
MAP reading at idle will mess with the fueling.

So many ways to get it wrong and only one way to get it right

Cheers... jondee86