How often should you use fuel treatment?
- Gas-injector cleaners should be used every 1,550 miles.
- Diesel-injector cleaners should be used in every tank.
In this regard, can you use too much fuel injector cleaner?
Fact is, you can use too much Techron and cause damage to your fuel tank lining. You mention the vehicle runs better after you use it. After you have it down that low, you should probably take around 15 gallons of fresh fuel. Check on the back of the bottle for the proper amount of Techron for that much fuel.
Correspondingly, can you put gas treatment in a full tank?
On a simple level, gas treatments work when they are present in the fuel before combustion. The recommendation would be to add any gas treatment you want to use during your fill-up, before you add more gas. And it's a more effective method than simply putting gas treatment on top of the gas in your tank and leaving it.
Many manufacturers are now instructing its dealers to not offer fuel injector cleaning or even the containers of cleaner to add to the gas tank. Some of these chemicals can even damage fuel injectors and emissions components, such as oxygen sensors and catalytic converters.