Rough Engine Idle

[ProjectM96]

Hello, I know most of you would reply MAF sensor.

Here is the story. I bought the car this past November, 2010.
The engine idle was rough jumping up and down, but there was no CEL light.

To my understanding from what I have read in Wayne's new book, 101 projects for your Porsche Boxster, a MAF sensor problem would cause a CEL.

That is why I do not think the MAF sensor is the problem.

Then, in March, the CEL turned on for the secondary air injection system. Can the two be related?
What do you guys think the problem might be?

Can the MAF sensor just need cleaning even though there is no CEL?