my '83 sd would often be low on power "running but barely moving"
turned out the vacuum shutoff circut was holding a vacuum. limiting fuel, my fix was to splice
the vacuum line to the shutoff box and recircut the vacuum line into the cabin where
i can shut down with a finger over the line when i turn the key off
need to make time to do it right yeah i know a redneck fix but it works.
and i get 28 to 29 mpg ~55mph 32 mile daily commute

Interesting I never heard of that manifestation but then I am more of a 602 guy just now learning about the 617 in the SD

thanks

I had the same problem talked about above. I did the values on my 300sd motor and went from 30+ to 20-25. My values were super tight at the time

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84 300sd 2.47 dif 360k
26 mpg needs lots of love
given to me in pitty

89 civic hatchback auto 140k
33mpgs soon to be low to mid 40's
been in the family since mile 1

85 300d with unknown knock. driven over 30k with knock and still going. sold for $800

You generally can't hear the turbo on a 617, but when it kicks in you should be able to feel it. The issue could be that described in Post 16, or misadjusted accelerator linkage not providing full fuel, or a problem with the ALDA or with the wastegate. None of these are terribly hard to fix.

Point out the rust and complain about the lack of power, offer the least amount of money you can without being insulting, and go from there.

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.

The answer is no. The car of topic, (300SD) was not capable of "37 mpg." I would wager almost any amount of money that 37 mpg cannot be duplicated under any normal driving conditions of the car and it's driving to any degree by anyone on a consistent basis. The car carried an EPA of 27 mpg in bold numbers on the manufacturer's window sticker. At least my '83 300SD did. I would have gotten it at some point ("37 mpg") in clocking my mpg on every fill for 8-years and 213K miles. It never happened.