Fuel economy suddenly dropped off 335d

gorsteve · 02-24-2019, 01:33 PM

Hi Guys, I would really welcome your comments. The economy in the car has dropped from about 40mpg to high 20's, car was showing a lambda error so I swapped that out and the thermostat as it was fluctuating a bit but neither has made a difference, no codes. Any ideas where I should go next, car seems to drive fine, dpf is regenerating etc I'm out of ideas.

328iX · 02-24-2019, 03:14 PM

Sounds like a broken n0x sensor

Assassin · 02-24-2019, 06:43 PM

Always recommended to change both thermostats - engine and egr. Any sign of a boost leak?

02-24-2019, 01:33 PM	#1
gorsteve Registered 0 Rep 3 Posts Drives: BMW E90 335D MSport Join Date: Jun 2016 Location: UK iTrader: (0)	Fuel economy suddenly dropped off 335d Hi Guys, I would really welcome your comments. The economy in the car has dropped from about 40mpg to high 20's, car was showing a lambda error so I swapped that out and the thermostat as it was fluctuating a bit but neither has made a difference, no codes. Any ideas where I should go next, car seems to drive fine, dpf is regenerating etc I'm out of ideas.
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02-24-2019, 03:14 PM	#2
328iX David 786 Rep 2,009 Posts Drives: 2015 328iX F31 Join Date: Nov 2018 Location: Temecula, CA iTrader: (0)	Sounds like a broken n0x sensor
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02-24-2019, 06:43 PM	#3
Assassin First Lieutenant 142 Rep 341 Posts Drives: M340d MHT xDrive Join Date: Dec 2018 Location: Scotland iTrader: (0)	Always recommended to change both thermostats - engine and egr. Any sign of a boost leak?
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