Applications: Electronic fuel injection: Mileage boost, pollution squelch: Electronic controls are designed to activate injectors, air valves, and fuel pump to improve engine performance

If your car's engine stalls, stumbles, surges, backfires, diesels, idles roughly, or is hard to start, you may have carburetor problems. Ideally, in its role as a fuel-metering device, a carburetor maintains an air-fuel mixture that is neither too rich nor too lean for the prevailing engine needs. But when the carburetor performs less than optimally, any or all of these problems may occur. U.S. Government-mandated exhaust emission requirements aggravate the situation by setting limits on the amounts of nitrous oxides, hydrocarbons, and carbon monoxide that are permissible in exhaust emissions. To meet these standards, carburetors are usually adjusted to operate at 15.6:1 air-fuel ratios and catalytic converters are added or, alternatively, air-fuel ratios in excess of 16:1 are used in lean-burn emissions-control schemes. In either case, the carburetors may not always operate at the best air-fuel mixtures for maximum drivability.