Q&A

 Master

When the check engine light is on, the controller's trying to tell you that there's a problem in the engine and emission control system which is sufficient to cause the emissions to be twice the legal limit - this usually means that the performance and mileage are diminished because the inputs to the computer are out of range. At this point, the controller has stored data and trouble codes for diagnostic purposes. When the light's blinking, it's trying to tell you that, in addition to whatever the light was on steady for, there's a danger of imminent catalytic converter failure and you should shut the car down to avoid catalyst damage. I don't know what the noise is but it could be an air leak in the power brakes or the engine air intake syste. Just a guess.
First thing to do is find a mechanic with a scanner to see what the light is trying to tell you.
Here's a directory link for you:
http://repairpal.com/directory?address=17601&car_brand_na...