My Punto 1.2 8v N reg has the problem you seem to be discussing re throttle changes.At tickover it will suddenly creep up to 2 or 2.5k on the rev counter and thendrop back. This only happens maybe 1/2 times a week not a continuous thing. Today i found it was holding my speed at 30 with no foot on the pedal!! Is there anything obvious i can check before giving to a garage :-(
Thanks