basically you need a tune-up, you also need check if any vaccum leaking, such as
small hose go in/out air-intake. You also need check if air-filter is very dirty.
If you go to garage for this problem, you should ask them why idle speed is
so low.
But I think after a tune-up in the garage, this problem can be solved.
1. check driving belt. if it is too loos, the alternator will not work well at low engin rotation.
2. check alternator, it may just started misfunction.
3. check EGR volve, if it misfunciton it can stop engin at red light/stop.
4. check distributor seeing if the cap needs to be replaced.