02 Toyota tundra won't idle. I put a new battery on and cleaned air filter

Remove the air intake hose at the throttle body, clean the carbon out of the inside using a brush and a can of throttle body cleaner, do this with the battery disconnected after cleaning drive the truck for about 15 minutes and the idle should be back to normal.

Your fuel pump is packed up and you should change you fuel filter as well its clogged

Idle problems are almost always a filthy throttle body, which is the most common thing to go wrong with our I6 engines. Clean this first, but disconnect the battery before you do it. We don't have a traditional PCV valve, so the throttle body gets dirty easier than other cars. Must be cleaned at least once a year or more depending on your driving habits.

Spark plugs other than AC Delco 41-103, or the Iridium versions of NGK, Or Denso won't idle as good also. Take Autolight, or Bosch for example, won't idle very well, or last as long.

These two things are the most common, if these don't fix it, check for vacuum leaks, new air filter, upstream 02 sensor. From there, it's gets more in depth and should look to a professional.

check to see if your air cleaner housin is loose or not on right
try taking cabe off battery for 5 minutes then put back on and try it

http://www.tundrasolutions.com/forums/engine-and-drivetrain/62759-battery-died-changed-now-wont-idle/

when battery was disconnected the computer lost its memory.the computer has to relearn its program to re- idle.

I recommending cleaning the idle air control valve. It get clogged with black carbon and doesn't work properly. It is easy to do and cheap. I understand it should be done periodically. I cleaned my husband's Ford F-150 IAC valve and solved the problem he has been having for, literally, years. My Toyota highlander '02 started acting up and I cleaned mine...worked like a charm. You use throttle body cleaner (spray).

See what cylinder is loosing (if that's it) spark. Use a spark tester if you can, or remove plugs and turn it over with the wires on all of the plugs, grounded!

The throttle body needs cleaning. It has some carbon build up, and when the battery went dead the computer lost its learned values, one of which is base throttle position. Now its reset back to factory specs, not accounting for a dirty throttle body. Seen it a million times