03 SXT idles at around 700 to 800. when stopped at light the rpm gauge drops slowly to about 550. Almost feels as if it will stall. had CEL that said TPS. put new sensor. car still acts up and at times will shake so bad and want to cut out. I did see a problem at the vaccumme line by the power brake booster. but I do not hear any more leaking and the car still does it. Can it be another sensor? what sends the proper voltage to the TPS. the code read input voltage to low. If anyone knows about this I would appreciate an answer or at least a place to start. thanks