95 e300d 125k. Trusted indy called me and said there wasn't any power past 4k rpms. He said a relay that controls a secondary set of "flaps" was getting power but not working. It is true that the car is a dog and never "steps down" at speed. I guess it doesn't step down cause the broken relay can't make the engine breathe enough. Does it sound like I understand the problem he was describing to me? Any additional help is greatly appreciated.

Yes, those are the resonance flaps in the intake manifold. Sounds plausible.

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Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References

Since I have never seen under the hood of an E300, what are those flaps for? Do they act like a throttle or just to lower intake noise?

They change the length of the intake runners. Longer path at low rpm = higher torque. Shorter path at higher rpm = better breathing for higher horsepower.

MB has not been sitting still. They keep improving these things.

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Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References

How about the butterfly valve on the intake of the 240's I've seen? They don't look like a shutoff valve since the clearance around them is too much...

Mine doesn't have one, so I can't help you there. But it has been written about here if you care enough to search for it. Maybe some sort of emissions control.

__________________
Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References

On mine it controls the vacuum the I.P. governor feels...