First starter (i thought) now low idle

So i had trouble starting my car over the weekend. Clicking from the starter, dash lights dim, so I assume its the starter. Later that day, I try to start it again, and it fires up. I had to take it to work real quick but then it wouldnt start up to drive home. I left it there and decided to come up the next day with a replacement starter and a battery charger, thinking the battery was really wear from me cranking on it. I eventually had it towed to a local repair shop and they said it wasn't my starter, just my terminals were heavily corroded and only charged me the $50 to swap them out. It turns over right away now, but I notice the idle is rather low, so low it is almost stalling out. I did stall out once or twice leaving the auto part store to return the starter. I removed the battery last night and put it on the charger for about 2 hrs, but this morning still a bit of a low idle. It hasn't stalled out today, but you can feel it wanting to at like 300-250 RPM. any ideas?

My first guess when I read this was the terminals. Next question, how old is the battery. If it older then 5 years, it's on it's last legs. Some have gone as far as 8 years, but I replaced mine at 5 to be safe.

You have in effect reset the ECU a few times now. It is re-learning. The idle should become normal in a short time.

Thanks for the reply. the battery was purchased 9/2010 so it's pretty new. I'm on the west coast now so it doesn't even go through seasons. I think the idles are starting to go back to normal, the drive home today wasn't as bad as this morning.