Still having weird problems with car limping

[bob6600]

Some of you are aware I've had intermittent problems with my W210 2000 E320 CDI limping when it feels like it. So far it has had the following done:

New MAF
New air filter
New MAP sensor
New thermostat
New oil + filter
Intake manifold removed and cleaned out
EGR mod done
All parts were genuine Merc

When the car is working fine, it has power and no black smoke, showing the mod is working fine. The car has been on STAR and was showing EGR fault codes (printer was not working but was told all EGR related by Mercland) so did the mod and the car still limps when it feels like it.

When it does limp, it has no boost in first 4 gears as it changes at max 2000rpm. If I build up speed, it will continue to build speed and go above 2000rpm (will do 70mph+ easily but slowly). Have checked for turbo pipes leaking etc and all seems ok.

Now the interesting bit, there is a particular daily journey where there is a large roundaboutat which I turn right and then onto the m/way. The r/about is traffic light controlled so can be approached with speed and when I do (with boost) car is fine. Once round the r/about I exit up the slip road onto the m/way. 99.9% of the time the car will limp here before or definitely on the slip road

Now, is this a fuel issue, fuel pump issue or something else?

Vehicle has never had a ATF change but could this cause this with lack of or dirty fluid? STAR has no other codes so I'm stumped

As always, any help appreciated

 

[Jane270ML]

Dodgy/intermittent earth strap connection?

 

[bob6600]

Not thought of that, but have checked the battery connections not long ago for something else and they were ok

 

[Mickybo]

possibility that the intake manifold motor is not resetting to the closed position correctly so the car thinks the flaps are jammed, have this problem on mine but 2 of my flaps are sticking and popped the actuator bar off. still does it sometimes just need to stop and switch car off and on again and its fine, will need a new intake manifold sometime tho

 

[bob6600]

I've checked the motor and bars and they all seem to be fine. Also if I turn the car off and back on does not solve problem

 

[Jane270ML]

After some searching, this is the earth cabling I was talking about... No start, no crank. Could it be the ECU? - Page 2 - Mercedes-Benz Forum

... it's from a USA forum.

Here's the page from mbilcats... http://mb.ilcats.ru/part/class/1/cc.../subtype/113/group/54/subgr/030/vers//imgno/1

look at page 2 on the above link for more wiring info.