Slugish and studdering on accelleration
 

OK so I'm getting my butt kicked this week.
Left Rear caliper locked up and lunches a set of pads and rotors in a day.
(young Driver) that's fixed but now the car is really slow off the line and it's surging at 3k.

This like fuel starvation.

It's also intermittent.

If you hammer down many time it will run through the gears in a some what normal fashion and accelerate fine.
Other time it hits a wall at 45 and won;t shift up or rev higher than 4K.

My son's DD is down for a cam adjuster replacement and he needs to run this old girl 70 miles RT to work on the highway.
Any quick checks I can make to try and address the problems?

Sometimes the tank screen can cause intermittent fuel starvation issues. Try switching the supply and return lines in the engine bay and see if the problem goes away. If it does then the tank screen is plugged up and needs to be removed and cleaned.

Another issue could be a clogged tank vent. After driving for a while pull the fuel cap off. If you get a big sucking sound the tank vent is clogged. It's under the rear on the end of one of the steel lines there is a little rubber bell shaped piece. Make sure it's all clean.

http://www.peachparts.com/shopforum/...-fuel-vent.jpg

I'll give the fuel line swap a try try since I just topped it up yesterday. As for the vent I'v not noticed and suction on the fuel cap on fill ups.

We'll see what's next.

If not an issue in the Tank the Fuel Filters.

Also at the end of the Intake Manifold is a Banjo Bolt that the Intake Manifold/Turbo Boost pressure has to pass through to send pressure to the ALDA on the Fuel Injection Pump so the Fuel Injection Pump will give more Fuel to match the Turbo Boost.
Check to see that that is unobstructed.

If you have an EGR try disconnecting the Vacuum Supply Line and Plugging the Vacuum Line.

I'll re-check the boost tube and bolt are clear. (Reciently Replaced) I'll als eliminate the EGR factor. ;) It's going to get a Diesel Purge and new filters are well. Less than 3K on the current filters but the car sat for 2 years. (full tank and treated fuel)

Check the transmission fluid level the way mercedes wants it done. The automatics can act funny with the fluid a little low.

Did this start after you topped off the tank?

Ditto, Have had this happen on mine recently.

If checking the other stuff gets no results:
Long Fuel Pressure Relief Valve/Overflow Valve Thread
Fuel pressure relief valve adjustment - PeachParts Mercedes ShopForum

Um, I had the same symptoms on my 603 this week. Turned out to be a clogged secondary fuel filter...

Cheap & easy fix.

This is usually the first thing to do with many types of complaints. In far too many cases the current owner has no ideal when even last changed.
]
May not fix the problem. Yet if it is the cause you may spend a lot of time and agravation until you get back to them. Just part of owning a diesel basically. Seems like possible fuel related difficulties perhaps change the filters. If not the difficulty put the removed filter into a plastic jar and carry it as am emergency spare in the trunk.

So the update on the issue. A quick inspection of the car was the driveablity issue were caused by low trans fluid levels. Some how the kick down cable fitting worked it's way out of the trans body and dumped a bunch of fluid. 4 quarts to be exact. Any way after wrestling that ting back in and confirming it snapped into place and a second top up for the fluid the trans is operating normally. I also had to tweak things including the kick down after the re-alignment go figure

I just can belive that fitting worked it's way out of the trans. Has anyone seen this. I'm blown away becasue it a ton of work to get it in while the trans was out.

A quick valve adjustment and tweak of the fuel delivery and the car is a different beast. Still a bit slower than I'd like but very reasonable performance. Now onto a diesel purge and an Oil change since the 0W40 seems to be de-carboning the internals.

I suggest a treatment of your tank with some Biocide, available at truck stops, marine stores and farm supply stores.;)

The biocide will kill the bacteria and break them up so they will flow through your filters and burn up.;)

Thansk for the suggestion. I though that Algae and other stuff that grows in Diesel makes your filters turn black over time. If so I think I'm OK I just wnat to clean the top end up really well.

They do. I like the clear pre-filters for this reason. They are much easier to see what's collecting. If you aren't getting black goo building up then you're probably fine. It's good to keep and eye on it though.