* Severity of the problem: A minor issue like slightly clogged injectors might clear up quickly, while a more serious problem like a failing fuel pump or severely clogged fuel filter may require more time or may not be solved by a fuel treatment at all.
* Type of fuel treatment: Different treatments have different strengths and formulations. Some focus on cleaning injectors, while others target fuel system deposits more broadly. A more potent treatment *might* work faster, but this isn't guaranteed and could even potentially harm your engine if used improperly.
* Vehicle make and model: Different vehicles have different fuel systems and sensitivities.
* Driving habits: Consistent driving helps circulate the treatment throughout the fuel system, potentially speeding up the process.
* Mileage: Higher mileage vehicles tend to accumulate more deposits, so it might take longer to see improvement.
In short: You might see some improvement within a few miles or even a tank of gas, but it's possible that you won't see any change at all, or the problem might return later. If the shaking and engine light persist after using a fuel treatment and driving a full tank of gas, you should take your vehicle to a mechanic for proper diagnosis and repair. Ignoring the problem could lead to more significant and expensive damage down the line. The fuel treatment is a potential temporary solution, not a guaranteed fix.
