1999 Vauxhall Corsa car hasitation whene taking off

whene moving off my car kind of jurks slightly the engine light is on dash but whene i get to just over 30 the light goes off on dash board and car is fine just seems to do it whene tasking of or in a high gear at slow speed or if the car is just ticking over whene im at lights the revs are going up and down like its reving itself so i have to rev it slightly hard to get it to tick over right but does not always happen the engine light stays on while i am sitting still dont think it is m.a.f as sombady said it would not run right throu all geers but whene i take out the throttle position sensor cable the car runs perfect exelent but the engine light stays on all the time could this maybe be problem and could i just leeve it unpluged or would it maybe cause damage if enyone can help on this problem would realy be a great help
p.s if this helps a got the car of my sister and it happend with her but the problem went away for a couple o months thene she run car low on petrol and filled it right up thene the problem started again?