I have a 06 tc that idles low and shakes gave tune up still the same it has header full exhaust weapon r intake but did this before exhaust work was done any suggestions

 

check the mass air flow sensor, remove it, look at both sensors the two dental floss looking wires down the tube and the amber bulb on the outside, probably dirty. Get yourself some CRC brand MAF sensor cleaner from autozone or oreilly (about $, gently spray many times both the dental floss and the amber bulb, let dry, then reinstall/reconnect.

the mass air flow sensor is right at the air intake box, but sounds like you have replaced it with a cold air intake, chances are if you're using an air filter that is aftermarket and needs to be oiled, that oil will get on the maf and mess up your idle.

also while you're at it, clean your throttle plate and throat. Don't spray the cleaner down the throat always onto a clean lint free rag and then clean. The intake manifold is plastic, and the throttle body cleaner can melt the plastic! But it's safe on a rag.

if your idle doesn't improve after cleaning the maf, then disconnect the battery wait a half hour, reconnect, start the car, do not hit the gas, let it idle for about 5-10min.. without any accessories on, the computer will re-learn the sensors now that it's clean.

 

x2