On the engines being produced today there is a Buick Fuel Injector for each cylinder in it. This is very different than the older throttle body versions that were similar in their appearance to a carburetor in which there were only two fuel injectors.
The newer Buick fuel injectors have the end of their nozzle directly in the combustion chambers in each cylinder. They produce an atomized spray of gasoline directly in the combustion chamber where it is mixed with the air that is introduced by the opening of the intake valve. This action occurs during each power stoke of the engine.
When the fuel is contaminated with particulates and the nozzle at the end of the fuel injectors become clogged or just partially clogged, the atomized spray will become a drizzle of fuel that will be powering your Buick engine. This is when the driver will notice a power drop off of their engine along with a decrease in the fuel mileage the engine will be obtaining.
The inside of the fuel injectors will also become coated with a residue. This residue is from the metal inside of the injector being exposed to the fuel and parts of it solids coming out of solution. In time this residue will narrow the channels in which the fuel travels inside of your Buick injectors reducing the amount of fuel that can reach the nozzle.
To help keep the fuel clean of particulates, a new fuel filter should be installed with every tune-up. For the residue problem, a bottle of fuel injector cleaner should be introduced to the fuel system on every fifth fill up of fuel. These two solutions are the only way to keep your Buick running at top efficiency for the driver to enjoy.