My 1990 vw jetta seems to either almost stall or fully stall as I slow down to an intersection. This seems even more common after the car has been in traffic and warmed up after a while. It usually starts up again but recently it didn't. I took it to a mechanic who said the battery has some circuit problems and they replaced it as well as confimed there results with a full " electrical test" for 45 minutes. Now it seems to still want to stall as I slow down to lights or to make a turn. Both the battery light and the oil light will flash on and off for a second during this time. Any ideas?