Using a "Top Tier" fuel from the begining should be enough to maintain the fuel system. The Top Tier list of fuels can be viewed by a search. High test will not clean any better. It's a slower burning fuel which is more resistant to pre-ignition.If the fuel system has been neglected with old or poor quality fuel, it is doubtful that any fuel or additive is going to have an impact in resolving any problem with deposits once the damage is done.. .Some may get lucky .A more aggressive approach might be needed for deposits affecting injector spray and intake valve deposits.

 

Are you speaking from experience or what you read?