If you just replaced/disconnected your battery and your idle is crap, don't panic. Probably means
you have a very dirty Throttle Body or
Mass Air Flow Sensor, both. The ECU learns to deal
with the dirty Throttle Body or
Mass Air Flow Sensor over time adjusting fuel/air/idle. Disconnecting
the battery resets the ECU, causing a learn all over again (approx 60
miles/one day worth of stops and starts). Try cleaning your TB and MAF sensor,
then try disconnecting battery. Should be good from the first minute this
time, because the ECU wont have to learn to compensate for a dirty Throttle Body or
Mass Air Flow Sensor.
