Maf Sensors Measure the amount of air flowing into a fuel injected engine. If you have a badly running engine and the engine check light reads P0101 then its likely time to replace your Mass Air Flow Sensor. Fit 03-10 Elantra/06-08 Sonata/03-08 Tiburon/05-09 Tucson/06-08 Optima/2006 Rio/2006 Rio5 /07-08 Rondo/04-09 Spectra /05-09 Spectra5 /05-10 Sportage/Fits 2.0L, 2.4L Models /Fits 1.6L, 2.0L, 2.4L