I'll help as best as I can...

I assume you've checked fuel filters? Replace them anyways. Have you checked for flow from the tank strainer? You need to pull the rubber line off at the tank and if fuel doesn't come out in a steady stream, you need to pull the strainer and clean it out. Don't forget to order the gasket for the strainer. Do you see any black dots in your clear in-line filter? If so, you have an algae problem and will have to treat with Biobar or similar product. Come back if you have algae and we'll go into that further.

Are you new to this car? Those machines sound loud on the interstate, that's normal. Either your trans is slipping on the interstate (very unlikely), your still in 3rd gear, or, it's normal. I think you should be turning around 3000 rpms at 70? I can't be sure as I don't have a 123 chasis 300D. This is a 123 chasis correct (81-85)? Do you have any thick smoke coming out when driving?

How about a valve adjustment? I could sit here for 30 minutes and give possible problems. Why don't you go check the clear fuel filter then report back and we'll be glad to help. If you have low power, it's most likely a fuel starvation problem.

Thanks
David

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2000 Honda Accord V6 137k miles

1972 300SEL 4.5 98k miles

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