I'll try the motor mounts first. I really dont think its the valves. When I give it just a little throttle it is smooth as silk. Excuse my ignorance but what and where is the RD bolt, I want to check into it.

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1983 240 D-SOLD
1979 300SD

Actually, valve adjustment is what I would check first. I'm not sure why you don't think it's valves unless you've actually checked. The problem is they tend to be too tight.

The rack dampner (RD) bolt is in the middle of the aft side of the IP. It's a bolt with a locking nut. (a weak rack dampner shows up as a rough idle while warm)

(BTW, just a little caution......refrain from using "gas" terminology such as "give it a little gas" or "throttle" as some will give you a little guff. We tend to enjoy "diesel" terms such as "fuel" and "accelerator".)

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Sam

84 300SD 350K+ miles ( Blue Belle )

RD bolts were on turbos only. I don't think a '79 has one.

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83 SD

84 CD

Mine acts the same as you describe when a glow plug is burned out. Quick and cheap to check and easir and cheaper to fix. Gook luck.

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1982 240D Euro Stick 4

at least on my 300 D turbo i adjusted the rack damper bolt and now it runs so smooth now...also adjusted the valves...

the link at the bottom of one of my old posts should help out...that is, if your 79 has a RD

http://www.peachparts.com/shopforum/showthread.php?t=180651

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1985 Mercedes 300DT

Thanks for the input, mine is a turbo.

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1983 240 D-SOLD
1979 300SD

All W116 300SD's are turbos.

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Joe

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1980 300SD - 495k miles - 'The Ambassador'
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Former Family Members
95 C280
73 280SEL
90 300D
87 300SDL (X2)
86 560SEL
84 300D
80 300SD

could be a few things out of spec, or close to being out of spec,,,

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Closing the store
Benzbonz.biz on your smart phone or tablet.

Learn something new everyday.

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83 SD

84 CD

Just went through the same issues chasing some heavy shaking at idle.

Replaced the injectors, adjusted the valve clearance, retimed the IP, checked for chain stretch, purged with cleaner, replaced the fuel filters, blew out the fuel line to unclog the strainer, checked the compression (325psi+/-5psi), nothing worked. Drove me nuts.

Then I replaced the injection pump. Voila. Smooth as silk now.

that'll do it

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'02 BMW 325i
'85 300D 450k
'93 190E 2.6 170k(killed by tree)
'08 Ducati Hypermotard 1100S 6k
'06 Ducati S2R800 14k(sold)