What is wrong with it?

[ProjectM96]

No CEL.
For the past year, I have been driving with idle jumping up and down.

I hear the sound of vacuum leak. I hear a blow or air every time the idle jumps every 1.5 seconds.

Mechanic insisted that it is not a vacuum leak. He told me it feels and sounds like it was running rich and that the MAF sensor was not being accurate. He just did the WD40 spray test all around the engine and hoses to make sure.

He recommended replacing the MAF sensor. Does everyone here agree? Remember, no CEL. I double checked for hidden codes by plugging it in scanner.

Also, there are two different part numbers for MAF sensor for the 2000 986 2.7L. I asked this question before, but got no responses. It is a 2000 model, but was manufactured in late 99. What is the right part number? The Price is $50 + difference between the two.