i notice everytime i add those fuel additives ie. seafoam, b12, lucas oil
my MPG goes down
aren't those FUEL additives suppose to clean the carbs and make MPG go higher
can anybody explain...

 

i dont use them. your gas should be clean just from the pump given that you buy gas from a good vendor with maintained tanks underground.

 

Fuel injection cleaner causes the engine to knock, so more fuel is used. More fuel use cleans the engine and then next tank better mpg. BMW Fuel Injector Cleaning Service

Knock from injection cleaning is cause by to much detergents which when cleaning forms ash and contributes to knock. Thats why its good to use a low ash oil less than 1 percent too and the reason to use a top tier gasoline so there no need for injection cleaner. B12 is a good cleaner and has high octane characteristics which should raise the mpg. I always got better mpg with B12 using a ounce per gallon.

Seafoam is an engine fogger and lucas oil works but is old tech. I would use Redline total injection cleaner with upper lube. Its hard to find but works Red Line Synthetic Oil - Gasoline Fuel Additives - SI-1 Complete Fuel System Cleaner

 

You're right, but sometimes you get a bad tank and it will dirty the engine and a good fuel injection cleaner is needed.

 

hey guys hi have one serious problem with my GD1 2001 Jazz running 5.5 or 6.0 KM/L in winter. What should i do I live in Mongolia. 30 - 35celcium in night 20 - 25c in day. and why fit have 8 spark plug.