why does my truck idle at around 2000 rpm's but only when my pedal position sensor is hooked up?

my truck was throwing the p0122 code for position sensor so I put new sensor on my truck but was still throwing the code on my vehicle and as i was checkin the wires to see if there was a short my truck started idling at 2000 rpm's and so i unplugged the wires and my truck ran really good. i checked the wires on my vom meter and they all seem to be working right and i also changed the computer but nothing is making it idle right with it plugged in.