The way that our injectors are designed they really never need cleaning. If you have a gm vehicle I would never clean them. The cleaner can damage the coatings on windings and cause them to short out. Ours are a little different in that they are dry injectors. As far as the engine decarbing, it is very simple to do yourself. I recommend GM top engine cleaner. All you have to do is get the engine warm and then remove a vacuum line and suck the cleaner in. You can let it stall if you want and allow it to soak. Then start it up and watch the smoke. Make sure you do this outside. I once saw a tech do this is the shop and it ran all of out for more than an hour. As far as stalling just take a look at the idle air control valve and inspect for carbon. You can use the same cleaner on this. They also make a spray version on the top engine cleaner for the throttle body.