I have 2005 sprinter with 227000 on it. I made the mistake of running Bio fuel in it 2 years ago. It ran OK for for a while but then I started loosing power and a injector failed. Installed new injectors and went back diesel. The power came back to a point, it's better but not what it was. My mpg is as good as its ever been but it seems like the turbo is not making the boost it once did. Engine is not as snappy if that makes sense. Any ideas of what I could try?