I just ordered a new rack damper bolt, cigar tube, diesel purge, new injector crush seals, synthetic oil and a bunch of other stuff I don't need but oh well. I'm going to toss a few things at it to see if I get lucky.

Today I took the car to work for the first time in the mountains. It climbed the first 2500ft hill just like my other 300sd and at the same speed. It's wide open for about 3 miles at 65mph. I have to think the #3 cylinder is working at above idle. The squeel is all gone, fixed by pulling the air cleaner and torqueing all the intake plenum(sp?) bolts which were very loose, some almost hand tight. I did try to adjust idle again and slow seems best but not good. I have a new gold rack damper coming. I think a few trips up the hill with synthetic oil and a diesel purge may help more than anything done so far. Does diesel purge clean the inside of the cylinders too?

Also does the rack damper eliminate a miss? I backed my current one out and the engine shook twice as bad then I turned it in and it smoothed back to the original miss/shake but half as violent. It still has a audible miss at the tailpipe. Could the new gold RD bolt get rid of the miss?

Uh, why new crush washers/heat shields? You DID use new crush washers when you swtiched the injector around, didn't you? Please say you did. :D

Not its intent. But I suppose it doesn't hurt.

Not a total miss that I have ever heard of, however, I got a parts SD many years back that rocked like hell at idle and ran bad enough that it seemed like a miss (pop pop out of tailpipe) and the rack damper bolt brought it back (after declared no good by one dealer and one indy shop... paid $300 for the entire car). That was in 2005 and the engine is still in use today.

Will it cure your problem? I hope so. No one can tell you that. These cars are old and each one has its own history.

Do you have any way to take a video (with sound) of your car at idle, both under the hood and at the tailpipe, which you can post to YouTube?

It seems that you can never have enough of the crush washers around. I always add a few in the order to make sure I have some around. Between my 3 engines and my friends car it makes sense.

I hope the RD Bolt helps. It runs great after 1000 RPM. I have changed everything else with improvement but not a total elimination of the shake. What exactly does the rack damper and rd bolt do?

Each car having it's own history is right. I believe these cars go so long that mere motal gas motors blow or are re-built before the strange stuff shows up. The engine I pulled out of my old car had to have over 500,000 and it ran smooth. Just a clack that drove me nuts. I tried everything to get rid of it. Pulled the motor and that fixed it with another engine. When I get time I will start to find out what the noise was.

If you want to clean inside the engine, use Castrol Tection Oil on your next oil change. It is known for suspending dirt from the walls to the oil, for the filter to trap it.