What do i need to do a full tune up on an 02 trailblazer

What is a "tune up" in your mind? Are you speaking of servicing your engine for engine performance? If so, I'd recommend replacing all spark plugs, ignition cables (spark plug wires), distributor cap and rotor. I'd replace your engine air filter also. And of course change the engine oil and filter. Wouldn't be a bad idea to replace your PCV valve also, if that has not been done. Your vehicle is 18 years old; it's really hard to make recommendations when maintenance and repairs may have been historically made on many components. All that said, I'd recommend investing in a good repair manual for the vehicle -- either online, at a place like www.alldatadiy.com -- or at your local auto parts store. There is great information in all those publications to be reviewed about vehicle maintenance and repairs.

It kinda depends on which vehicle you have - I see Blazer AND Trailblazer posted.. Completely different engines!