Need help and advice ?

Hello.i need help please.i have a 2000 Corsa and seems to be a problem.if I'm sitting in traffic and leave the car idling it will go into safe mode and I'll have to turn the engine off then back on.however if I keep the revs off 0 it's ok but it means that I can't even relax in rush hour traffic it's really annoying me.i have a big tail pipe Aswel so I look silly making loads of noise and not moving help would be really appreciated!!!!