Toyota Repair: 02 toyota Sequoia stalls after battery change, toyota sequoia, car idles

Question
This afternoon we accidentally left our lights on for about 20 minutes, the car didnt want to start but after waiting about 15 minutes it cranked over.  So we didnt shut her off we went straight to get a new battery.  Now the car idles real sluggish and stalls in idle and at stops.  we had to drive all the way home 2 footing it so that the enging did not drop below 1k rpm.  We had to drive about 15-20 minutes, about 10-15 miles. When driving the voltmeter is up btwn 16-18.  When I take foot off gas it drops significantly.  She seemed to be running fine before this afternoon.   some other posts suggest the ECM if this is the problem how long will this take to kick in and reset? What other suggestion do you have that could be the trouble.  THANKS!!

Answer
Disconnect the negative terminal on the battery again, wait ten seconds, reconnect it and go drive right away it in stop/go drive cycles as well as highway, the onboard computer has the ability to relearn the driving patterns and should be back to normal after a while.