New Battery Installed = 3K RPM's and Thermostat Malfunction? Any Suggestions Why?
 

Yesterday morning it was -15F up here in the frozen tundra of Minneapolis and my car would not start. Got a jump from a snow bunny and decided to replace my battery. Bought one that night at Sam’s Club, installed it. Started up the car and it started right away but it was at 3K RPM. So I shut off the car, started it again and the RPMs started at the normal level. This morning I tried starting and it was -23F, took awhile to start but it did. I’m driving and the temp needle comes out of the black and I turn the heat on, nothing but cold, cold air. So I’m like ok this sucks, seems like a thermostat problem (FAQ write up), Temp needle went to standard warm temp for awhile while driving and then dropped to nothing.

Also at a stop light this morning after getting off the Freeway, the idle was at 3K again.

What gives? Why would replacing the battery give me these problems? Please let me know what’s going on here and why these issues would only occur right after installing the battery? Thanks in advance for your thoughts/help.

You need a new thermostat, the heat should come as soon as it reaches the "C". As for the 3k rpm idle, i have no idea. How the F was the car not moving at 3k rpm at a stop light? You sure its not 300 rpm?