just one clarification on this does it do it all the time or only some of the time? as one possiblity is (kinda hard to explain where it is but will try my best) there is a little clip that olds the throtle cable in place just to the right of the throtle body on the front this may be sticking caused by perhaps a freaying cable inside it happened to my mothers lanos was a case of taking the throtle cable off the body pulling back the protective sheefing and checking for any damage.