i have a '93 that will go through 1 to 2 throttle positioning sensors every year. does this seem to be a common problem with the cars, or is there a more serious problem that this could be a symptom of?

Derek, please put your car'* model and year in your signature line. Select User CP at the top of this page, and then select Edit Signature on the left side menu of the page that comes up. This helps us to focus in on your issues more quickly.

Obviously having to replace a sensor every 6 months to a year is a problem, but I will let one of the Gearheads take a shot at what the problem might be.

That is not common. Test the wires for high resistance, check the terminals for any corrosion, test for any shorts. Check the voltage