low idle stall when coming to stop

I just recently had new battery and starter put in.before this my engine service light was on for about a year code said it was something with the idle .After starter was put in I drove it .I noticed no service light even tho the computer was reset.the idle was definitely lower before it would start right up ,without touching the gas pedal now I have to press it a few times .and it has also started to stall as I don't touch gas pedal and am coasting to a stop.is there a vacuum leak or do I just have to turn up the idle. I also read when changing the starter the intake gaskets need to be changed could this be the cause. THANKS FOR YOUR PROFESSIONAL INSIGHT