No mechanical adjustment for the idle. It can be raised if you connect into the DME, however it shouldn't be surging. Fixing that may bring the idle up to where it should be.
Have you ever cleaned the throttle body and MAF. Also check all of the ducts from the MAF to the throttle body for cracks, same for the vacuum lines under the top engine cover.
Not sure what Innova you have but most OBD readers are better, quicker, and easier to use than a Peake, IMHO.
2000 540/6 Slightly tweeked...everywhere