96 (Auto) Altima throttle problems

I have a 96 altima with an auto tranny. Everytime I will step on the accelerator a little harder than usually making the auto tranny downshift a gear, the throttle gets stuck and the rpm's keep rising until I tap the accelerator a bit harder to lower the rpm's to normal. I am pretty sure that the throttle switch located in the engine bay is stuck due to dried oil or it could be an electrical problem. I am going to use some wd40 lubrication to spray it down for now. I will update this thread if this problem arises again after to spray the wd40.
I the meantime can someone out there give me some advice.

thanks in advance