Is my MB shop taking me for a ride $$$ ? Help...
I have an 86 300E. She ran like a baby until last week. She suddenly felt as if she were losing power. After I restarted her she sounded like a U-Boat almost like a diesel and ran really rough. A day later a attempted to crank her up but she would not catch I had her towed to a highly recommed MB shop who informed me that it was a fuel pump and filter. After the fuel pump was replaced she still runs very ruff and sounds aweful. He then told me that it was an electrical problem ( fuse box or something )and that I had some burnt wires. This just dosn't quite sit right with me. I'm hoping it's not the case but I'm thinking valve or piston. What's you take?

1. Loss of power
2. Loud knocking
3. Would not start < strong crank >
4. New fuel pump and filters
5. Constant knocking - Rough

Need your help. What do you think?