Frankly, I'm in complete agreement with stevebfl. Being a do-it-yourselfer is a wonderful thing with many advantages, but it's important to realize one's limitations. And by limitations, that's not necessarily a consideration of just your personal skill or experience, but also of tools and equipment that you have at hand. Mercedes gasoline fuel systems are extremely complex and require certain diagnostic equipment that very few people have access to. And the fact is that many of the components involved are simply too expensive to simply swap out and cross your fingers.