Most gasolines have them in at teh pump already, but some are better than others.
It's somethign you can eitehr buy at the autostore (such as Chevron Injector cleaner) and put itno your tank.
I alwasy gas up on hi detergent gas (Chevron) so i only add a bottle with every oil change.
The best detergens additve known to this board is BG44kIt comes in many packages, some for rail flush some as fuell additive.
The cative ingredient in Chevron Techron is the "BG44k" chemical.Expept its at nearly 100% in a bottle of BG44k and a 2 or 5 % (forget which) in a bottle of Chevron techron.
As you can imagine its very strong, best add to a full tank.It's also vey difficult to get.The company doesnt bother with the retail market so you will find it most often at quality repair shops.
Many (but not nearly all) Infinti dealers also carry it and use it during their periodic services.many some Nissan dealers too, never checked yet.
Fred...
