I should have provided more details: I use an injection service tool that is air pressurized to push the cleaner into the fuel rail. I run the pressure a little below the FPR psi so that the cleaner does not get pushed back in the fuel tank by the FPR. The cleaner is combustible so the engine idles while the cleaner runs through the injectors and cleans the backs of the valves also. Only trick is to disable the fuel pump so it doesn't compete with pressure from the service tool.

Surprising what a service like this does to improve the running on some engines. Not sure if some engines build up deposits because of their design, the ethanol in the fuel or some combination. It will be interesting to see what happens on the V70 (170K miles).