Toyota Repair: Tune Up, air fuel mixture, emission control system

Question
 Hello, I have a 99 Tacoma V6 pickup with SR5 package with 66000 mi. on it. The check engine light came on and I decided to get a tune-up ( it was time for one anyway). Should I ask for a regular tuneup or must I be more specific. I would like everything checked out, (ex. timing belt, and valve gaskets) so nothing breaks down the road. What should I look for? How much is a general tuneup? Your advice would be extremely helpful. Thank You!

Answer
Before doing anything I advice that you find out the reason why the check engine light is on, a diagnostic scantool needs to be connected to see what the trouble code is, once you have that information you can get back to me for further assistance.
Most of the time check engine lights come on because there is a failure in the emission control system.
Other than replacing the spark plugs and the air filter there is really no such thing as a tune up, the idle speed, timing, air fuel mixture etc. are controlled by the computer and are not adjustable.