I have a 2010 Mazda 6 6 speed. It would not start in the morning. I jumped it off and it ran fine. After being off for about an hour it started fine and ran fine. Only drove about 5 miles. Went to get back in about 2 hrs later and it wouldn't start. Had it jumped off and something wasn't right. It idled high. When in gear the rpms were high without pushing gas. When I would put on the brakes I could feel the car working against it. Help!

 

I would concentrate on the potential battery issue 1st & get that sorted.

Then see if you still have idle issues afterwards.