In the result of corrosion phenomena in automotive metallic fuel tank, a layer of rust which consists of hard and micronized oxide grits with low cohesion and adhesion could appear. Through gasoline delivery from fuel tank to chamber of combustion, these hard and micronized grits could cause erosion and service problem for the components in this rout. In concept of after sale services, some defective parts such as fuel tank, injector pump, nozzle of injector and etc, needs to be repaired or changed due to the corrosion. In this article in order to improvement of corrosion resistance, some investigations into the recognition and assessment of corrosion in which relative these parts have been done. The corrosion mechanisms such as galvanic corrosion, general corrosion have been recognized. Based on this information modification and improvement are concentrated in field of welding, plating showed considerable improvement in corrosion resistance.