Pontiac Repair: catalic convertor, vacuum hose, catalitic converter

Question
QUESTION: can the catalic convertor make the car sthl at a red light or at a stop sign,and if you start the car again when shift to drive stahl agin?

ANSWER: Model of car and year and engine size transmission # of speeds???

---------- FOLLOW-UP ----------

QUESTION: pontiac gram an 1995 quad 4 2.3 engine 4 speed automatic. 1600000 miles

Answer
Hi Ray.
No, a catalitic converter shouldn't cause that if you had a bad/plugged converter the engine would lack power under accelertaion. If this was a 3 speed trasnmsission and it felt like a Manual trasnmission that you forgot to pusth the cluth pedal in at a stop that would be a torque converter issue. Have yet to see that happen on a 4 speed trasnmission. I would take a look a a couple of things. Make sure the throttle plate and Idle control motor are not all gummed up if so clean them with air intake cleaner and I would take a look at the vacuum hose that runs from the intake manifold to the bottom of the MAP sensor amke sure the hose in not sucked closed or split.