We have a 5,000 mile trip coming up and I will go thru a few gallons of fuel.
I just bought a qt of Lucas Injector and fuel conditioner at Walmart. 2-3 oz per 10 gallons = 16 oz per full tank
I don't have any problems but I was told it does cleanup any emmission hardware that may have carbon built up like plugs and exhaust monitors.
My exhaust pipe does have some carbon buit not much. We will see if it helps with unburnt fuel reduction.