Do fuel injector cleaners actually work?

The consensus among specialist communities is that PEA-based cleaners (Chevron Techron, Red Line SI-1, BG 44K) do measurably reduce carbon deposits on injectors and intake valves over a tank or two of driving, while non-PEA "fuel treatments" function more as upper-cylinder lubricants or stabilizers. Don't expect miracles on a healthy engine, the bigger gains show up on neglected or higher-mileage vehicles.