I had the fuel induction service done on my direct inject STS engine at about 65k miles. The throttle had stopped being very responsive to input & the car would lose speed up hills to the point I thought something was really wrong with it. It has been like a new car since the service & caught me by surprise with the response the first time I got on it after it was done. I've been more than pleased with the results.
I don't know if this is appropriate for a throttle sticking issue, but seems in the range of reasonable things to try. To me it seems more critical to do it with DI engines because, from what I've read, they get carbon buildup in places where fuel injector cleaner put in the gas tank won't have an effect. I'm not sure how effective it would be for a non-DI engine & the results may not be so dramatic.
Price sounds close to what I remember mine costing, but my dealer didn't recommend it until the 50k mile mark as a routine service.
