2014 Buick Lacrosse
my 2014 Buick Lacrosse idles roughly and stalls when stopping or standing. It
always restarts. Mechanic says it's the starter but that doesn't seem right. ANy
I agree. What would the starter have to do with a stalling engine? If the engine always restarts, I'd say the additional problem is this particular mechanic. Your symptoms are frequently caused by a vacuum leak. It could be a vacuum hose, or a defective device, like the EGR valve. Might be a dirty MAF sensor and throttle body. Take the car to a qualified mechanic and have this diagnosed; it probably isn't anything serious.
I had a Buick Regal that stalled while driving and it was a Throttle body with a leak.It is expensive I got lucky and someone I knew had a spare used throttle body around that I got cheap.