First, find out if the throttle plate really is sticking in the throttle body. When the car is cold, disconnect the throttle cable and see if the throttle plate is sticking by trying to open it by hand. Sometimes the sticking is only present with the engine running so start the car and see if the throttle is sticking by opening it by hand. If there is no sticking with the cable removed, look elsewhere for the sticking, such as the cable or throttle pedal.
Next, remove the intake tube and look inside to see if the throttle plate is actually digging into the throttle bore. If it is, and you are still in warranty, take it to the dealer and ask for it to be replaced. If the throttle plate is contacting the throttle bore, you can adjust the throttle stop just enough to keep the throttle plate from binding. Only move the throttle stop about 1/8 turn at a time until the clearance is OK. Don't move it more than a total of 1/2 turn. You will throw off the throttle position sensor setting if you go too far which will create some drivability problems.
I clean my throttle body often. Probably about every 10,000 miles, sometimes mofre often. It has been dirty enough to stick only once or twice. every time I clean it I notice an improvement in performance, especially the part throttle response.
The sticker on the throttle body that says not to clean it is because of the teflon coating on the throttle bore. The teflon coating is supposted to make it so that it never needs to be cleaned. Although the teflon coating does help to keep the gunk from sticking as bad, it still does get dirty, and should be cleaned as a matter of maintenance from time to time. Because of the teflon coating, you must be gentle when cleaning the throttle body so you don't remove the teflon. The teflon coating also makes it easier to clean.
