03 grand am transmission is changing hard and sometimes will shut off when you are sitting and idoling could a map sensor cause this or what could? Thanks

Have you changed the transmission fluid and filter on a regular basis? This is the most important thing you can do for your ATX. I recommend Mobil 1 Synthetic Multi-Vehicle ATF, to ensure transmissions shift properly, last a long time, and get maximum mpg. The stalling problem sounds like it may also be a general preventive maintenance issue; e.g. changing spark plugs. Change platinum spark plugs (ACDelco only) every 50,000 miles. Be sure to also check for any codes. If the problem persists, test/replace the ignition control module and coil packs.