Rough Idle, then Running Fine

Yesterday I disconnected the battery terminals to clean the corrosion off. Later I did some errands. Two stops, total about 6 miles. Truck idled so rough I thought it was going to die. Really rough at last stop, but when I got home it seemed to idle normally and driving it today, idle is normal. This is a 2011 Tacoma with the 2.7 4 cylinder engine. I bought new and it has never done this before. What might have caused this?

 

Most likely the throttle body is dirty, wouldn't be a bad idea to clean it.

Disconnecting the battery clears learned values including learned idle, it takes some time to relearn especially if the throttle body is really dirty.

 

I have seen a good number of other posts with people reporting the same after disconnecting their battery. I don't recall them reporting how dirty their TB was

 

Toyota seems to be a bit more fussy about things after a battery disconnect partially because they won't even begin to do any adaptive learning until coolant temp gets above 174F.

Any slight buildup on the TB will cause poor idle quality until it relearns, if the TB really dirty it may never fully relearn until it's cleaned.
I can't tell you the number of vehicles with poor idle quality I've fixed by simply cleaning the throttle body and doing an idle learn reset.

 

Thanks for the replies. I took it to a mechanic today to fix a mistake of mine unrelated to this thread, and asked about the throttle body and the battery disconnect, and he said exactly the same as mentioned in this thread. The thing about this that didn’t make any sense to me is that the computer has to relearn everything when the battery has been disconnected, but I’ve changed the battery a couple of times and I know I’ve disconnected the battery to clean terminals before and this has never happened. I decided to leave the throttle body alone for now.