From my understanding of your explaination, I think that it a list of things needed. A tire for one of the rear wheels, and a throttle position sensor. Getting the tire is easy. The throttle position sensor may be dismantled and the cars needs one. Or if it has one, usually the car will not hold any speed very well at a given position of the gas pedal. In other words, your speedometer will fluctuate when you are holding the gas steady. Test it out to see whats up.
