i was sat bored earlier waiting for the wife to come out of the shop so decided to check if the revs stayed steady when i pushed the accelerator pedal and checked it at 1k, 2k, 3k rpm and it wouldnt hold steady. it was going up and down. when i held it just over 1k it increased to 2k then back down to where it was and no i wasnt pressing the peddle and harder . the car is a bit jerky on gear changes and hesitates now and again under acceleration. any ideas what this could be? its a 1.8 16v sri
oh and it was serviced on sunday.