E46 320d Poor Acceleration

I have recently purchased a 3 year old 320d Tourer and it has a couple of
problems that I am hoping somebody can help me with.
1. The acceleration is pretty sluggish (not to mention ambarrassing) and
actually slows down from around 70mph in 5th on a slight incline with full
throttle! It seemed okay when I bought it 3 months ago but I am at a loss as
to what is wrong - any suggestions please.
2. The rear window switch has an annoying habit of occasionally unlocking
itself automatically (unless I centrally lock the car before driving). It
will unlock using the key fob but whilst unlocked it will not manually
operate (the key being the only way to open the window). Has anybody had the
same problem and know what the solution is please?
With regards
Reply to
Cheryl Davis
Yep been there done that Almost certainly a duff Maf sensor I bet the fuel consumption is awful as well and you have to rev the nuts off it at a roundabout to pull away.
This seems to effect every BMW/VW/Merc diesel lump including the 530d
Simply unplug it and go for a drive Take the engine top cover off it is the thing behind the oil filler in the air intake pipe going down to the turbo.
The car should immediately be lots lots better I have a Rover 75 with the same engine Drove it to Farnborough and back (400 miles) with it unplugged and got 51MPG!
New sensor £150-200 at a dealer Ebay up to £120 but be warned duff ones still look brand new
If it is the sensor don't change the entire housing which is what you will end up buying as the lower screw is a pig to get to all you need to do is undo the two security screws holding the actual sensor in the housing and change just that, much easier
Does it have an after market oiled air filter if so get rid of it as the oil droplets can destroy the sensor
On Rovers fine water spray has been known to get past the air filter and cause failures
These sensors are notorious for failing just about anything seems to wreck them dust flies anything mine had a spider on it.
Some people say they can be cleaned but I wouldn't bother as you have no real way of telling if it is working properly.
Ron (link below) sells an amplifier to boost failing sensors, but mine I think was totally dead.
They are made by Bosch, they have not so far had the decency to offer low cost replacements, mine lasted 30000 miles only
VW however admit they fail and offer an exchange price but BMW and Rover still prefer to rip people off, they are so unreliable that I have even seen suggestion that they should be service items
They degrade over time so you don't really notice the loss of performance and higher fuel consumption initially.
many people get their cars chipped and effectively only recover the performance lost by the duff sensor
a good site for info is
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Rover bias but this guy knows his stuff the Pierberg MAF will fit your car and is a lot cheaper.
Re Window pass :-)
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