Just bought a brand new Cobb ap, flashed to stage 1 and immediately noticed a faint buzzing noise that would become louder or go softer depending on my throttle position. At first I assumed turbo, but then realized it was the ap. I emailed Cobb and they said:
"It is likely going to be due to a wiring issue in your car like a bad ground. That means that the current is not stable through the electrical system and can cause problems with both the AP and other parts of the car."

I've read about this problem in the focus st and Mazda forums through a Google search but nothing on evo x forums. People have generally traced it back to a faulty ap. Has anybody experienced this problem and if so how did you fix it?

 

Not sure how they say this since the unit plugs directly into your ODB sensor? I'd request a replacement to see if the next unit does the same thing. Telling you that you have an electrical issue out of the gate seems odd considering how the thing is connected.

That being said, you don't need to leave the AP connected at all once you flash it. I'd just leave it in your glovebox until you need it again to read an engine code or something. Leaving it attached is asking to get your car broken into, and if you are using it for gauges there are better aftermarket solutions that are much more accurate. And since you are 'stock' with just an ECU flash, the need for gauges at all is minimal.

 

thanks for the reply. I do have it put away atm.

 

I have had this same issue with two different accessports, not sure why it does it but i have just gotten used to it.