A4 2.5 tdi mpg dip (2004)

[nodrog]

I've had my A4 2.5 tdi multitronic from new, with 138k miles on the clock. The car has been faultless, is serviced every 15k on Audi long service and the miles covered are virtually all motorway.

I have a 90 mile round commute to work and have normally averaged 40/43 mpg, but fairly recently the mileage had dropped to 35 mpg with no change in my driving style. Car was serviced in December, with all filters changed and no code faults were found.

I have also cleaned the MAF, with no change to MPG.

I've also noticed that upon firing the car up in the mornings, there is a small cloud of smoke from the exhausts which quickly goes, the car also feels very sluggish between 1000-2000k revs, seems to take an age to reach 90c temp and the climate control never gets hot or cold (dispite being recharged recently and no faults/leaks).

I would be really appreciate any suggestions. Thanks

 

[adamss24]

Is there any yellow light on the dash ? The 04 models have a host of electronic gizzmos to keep green peace happy: water cooled EGR, motorised throttle body, extra fuel limiters built in the injector pump and extra fusy ECU with carefully grafted smoke maps ! First thing i will do is get rid of the EGR valve cooler, the throttle body and delete the EGR valve from the map. That will free a few Bhp and let the engine breathe better !

 

[nodrog]

Hi Adam, there are no yellow lights on the dash currently. Last time the warning light came on was Oct 2010, then had the temp sensor replaced. Can I clear the egr value cooler, throttle body and etc? Thanks for your advice