Engine power. The idle bouces between 2,000 and 2,500. It starting to do it now without the ac on.it happeneds every single time the ac is on. When it happeneds I pull over, shut of everything let it sit for 20 mins and it stops. If I try sooner than that it happends the sec I put it in drive. Please help as its getting worse

Middle column that got hot enough to melt floor mat. What would have caused this? 2) why when someone sits in the vehicle for an extended pediod of time (a number of hours) the vehicle wont start? Has occurred multiple times and had battery changed. On one episode there was a clicking noise and some flashing of dash light just before it happened. It does not do this if the engin is running during the time someone sits with the vehicle for an extended period of time.