Internal engine cleaning?

Next oil change, run synthetic. If you can afford it, run synthetic for the the next 2 changes, It should take care of any sludge you have. Cant say much for the broken valve seals lodged in your pickup already. As for cleaning the cylinders, Seafoam is fun, but dribbling water into the high idle carb works great too, and is free. Just point it away from property, do it in a bank parking lot on a sunday morning.