What is ultrasonic bathed? I have been a mechanic for 7 years and have never heard of that. The best thing to do to get injectors cleaned would be to find a mechanic workshop that is an authorised Carbon Clean workshop. Pretty much it is an on car injector & fuel system cleaning machine that I personally believe is the best available on the market. It cleans the fuel rails, injectors, carbon deposits built up around the valves/combustion chamber/piston crown, the O2 sensor & the cat converter. You will pay around $180 but it is well worth it. You pay similar prices just to get someone to pull the injectors out & put them on a bench cleaner. Bottles of fuel system cleaner only work after many treatments and you will not see an immediate results