w210 e320 cdi wont accelerate properly

[Smaltze]

i made a thread about this before but id rather start a new one now that i have more detail.

Car used to be fine, one day driving the problem just started.

everything feels normal, kick down works, can still drive fast.

triptronic works perfectly, holds the gear in and lets me rev to redline.

however in drive whenever accelerating it cannot surpass ~2.8k revs or so it seems, may be 3k and im reading it wrong, or below but its very consistently that exact spot.

when i kick down it will downshift and pull hard until the revs hit that mark and then instantly hesitate and hold the revs. they will then sortof bounce back a bit and try again but just get to the same limit. this whole time the car is doing its best to accelerate and will still reach proper speeds. the only difference being it wont rev up!
it will often bounce around the mark for a while until it wants to upshift and then repeat in every gear. so it still accelerates at a great pace.

when driving on the motorway i did test it by driving fast enough for the revs to naturally go over 3k due to engine speed and it did it.

it also revs up absolutely fine to redline in neutral.

things ive tried -
driving it with the MAF unplugged, no change.
adjusting the VNT rod on the turbo so that there wasnt any odd flat spots or anything, no change.
ive also shunted the egr in the past which fixed previous limp mode.
the car is remapped fairly strongly.

could it possibly be the throttle position sensor etc?
also i might add, i somewhat sense general lack of power overall, but if there is its slight and it could only seem that way because of the nature of this problem.

 

[Doug1234]

My take would be to have a chat with the company that did the mapping as it may be a common glitch they have come across.
A forum member recently had a blocked cat on a w210 e300td, although that put a code up, so check exhaust is free flowing.
Check air filter and air intake for collapse.
An engine will rev to redline in neutral even if only half the cylinders are firing, it needs to be working / pulling the car to show up any problems

 

[bembo449]

well I have a mapped diesel alfa and even thow I had a delete done on the EGR at remap time , ive still had an EGR fault popping up every few miles , the car drove fine thow so its not the same as yours but my point is that a delte or shunt is not a sure fire reason your fault cant be the EGR

 

[Steve@Avantgarde]

Sounds like you have done everything but get it on a STAR machine and check the fault codes, which is where I would start before you guess wrongly at anything else.

 

[om613]

Yup, proper diag. is the way to go.

I'd be changing the fuel filter first, though, as it's cheap and easy to do.

A blocking filter is a physical restriction to fuelling that limits revs and gives a performance 'drop off' which you've noticed.

 

[Smaltze]

I'm in Surrey, anyone have any recommendations for a STAR read? Cheap as possible