Posting your son's symptoms will aid in making sure you are repairing/replacing the correct part.
If you have a CEL (check engine light), get the code read for free at Autozone, and give us the code (not the description they give you.. the actual code: Pxxxx, where X = 0-9)
Tell us the mileage, make, model, year, and trim of your vehicle, as well.
Ray