weird acceleration

hi bob and ken i have a 91' crx si with 122,000 miles. it is my daily driver and the check engine light will appear after 10 to 30 minutes of driving. i have noticed that my car does not accelerate consistently, what i mean by that is if i push on the accelerator at 25%, my car will some times go really slow or it will accelerate normal for the throttle being pushed at 25%. i also have noticed that as soon as the check engine light appears their will be a slight drop in power, also the acceleration it self acts some what violent( jerking almost as if it was not getting enough gas). my uncle tells me it might be my Throttle Position Sensor. as soon as i turn off the car and allow the computer to reset itself, the light goes away but the engine still has the same problem just with less violence. and after a few minutes of driving the light is back. what can it be?

thanks, Eli