It doesn't matter how powerful your engine is on paper if it's not getting the right air-fuel ratio. Fuel injection problems mean low power output, wasted fuel, noxious emissions or heat and friction damage to the engine. Fortunately, there are plenty of ways to fix this, ranging from improved air intake systems to fuel filtration, that give you the horsepower you're missing, often at less expense than other engine mods.
Why Air-Fuel Ratio Matters
Internal combustion requires both fuel and air, delivered to your engine as a mixture of air and atomized fuel, in a ratio that varies during operation. The ideal air-fuel ratio, where no excess fuel or air remains, is called the stoichiometric ratio or "lambda 1". This ratio depends on the fuel used and, in practice, the engine design as well. Rich mixtures, containing more fuel, tend to burn quickly and output higher power while lean mixtures improve fuel efficiency with a slower burn. However, too far in either direction can dramatically worsen performance or even damage the engine, manifesting in symptoms like thicker emissions or engine stalling. Even lambda 1 is dangerous under high loads since this creates the hottest, most intense combustion.
Fixing the Fuel Injection
If your vehicle consistently runs rich or lean on average, it can adversely impact performance and engine longevity. There are a number of common causes for this behavior. Often, the problem can be traced to faulty sensors making the ECU unable to properly monitor and adjust the air-fuel ratio. Alternatively, there may be clogged filters, either for fuel (if lean) or air (if rich) intake. Even if there aren't any outstanding performance problems, it sometimes helps to install a new air intake system for an increased and cooler air supply. Improved fuel filtration, on the other end, allows better control of fuel injection by removing impurities and dissolved air, so that more of what's injected is actually fuel.
Exact air-fuel ratios are complex and, for usual operation, not especially important. However, knowing when something is wrong with the mixture and what to do about it does wonders for your vehicle's life.