I have recently changed the front right headlight (requiring some vacuum lines temporary being pulled). I have since then also replaced a few of the lines and connectors on that side of the engine, as they were old and I hoped would help fix this issue. I've also very recently replaced the shift bushings on the shift rod (ok the old ones had worn out so much they were physically missing).



Symptoms .. (about 50% of the time starting out) .. for example .. pulling out into an intersection after being stopped at a red light... car will have zero power, stick for a moment at 2000 rpm .. then if I pump the accellerator, will 'catch' hard into gear and a bunch of smoke out the exaust and will then regain power.



Other times, it seems to be fine?



I'm going to try and grease the throttle and turbo moving parts, and also put in a new air filter.



Any diagnosis tips?

The first thing to check is the Alda sense port. This should really be a permanent sticky:

https://www.peachparts.com/shopforum/diesel-discussion/385395-sluggish-87-300d.html#8

1993 will have the vacuum operated wastegate. Go back and make sure everything is correctly routed and that you haven't unplugged anything electrical going to any of the vacuum transducers or switchover valves. If you don't have vacuum holding the wastegate closed, you have no boost.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

I changed the air filter, and while I had it out, I replaced a couple more vacuum lines under the air filter and then I checked a vacuum line on the driver side of the engjine. There is a small rats nest of vacuum lines there, with one of them going to a very small tube that comes out of the engine about 1/2 an inch. For some reason, that line was split almost in two, right by the clamp. I pulled off that 3-4 inch piece of hose and replaced it. I had to search a bit to find a hose clamp that small. The original was some strange clamp that looked like it was probably put on by some special tool. I haven't replaced the fuel filters yet, but, the car seems to be back go it's normal self again. I can't tell for sure, as it's been cold here, and should know for sure when the weathers warms up a bit. No more smoking or low power when starting out now. I think it was probably the small hose going into the engine tube. I wish I knew what that small tube was. It's amazing how a small hose being cracked can modify the engine function so much. Thanks for the tips!!!

Turbo boost sense. It transmits manifold pressure to the Alda, which adjusts fueling.