Audi A4 2.0FSI sensor problem?

I have a 2003 Audi A4 2.0L FSI Sport that has a flat spot on acceleration, increased fuel consumption by about 20%, a variable tick over speed and occasionally when starting the engine fires but then dies or the revs drop to almost none then picks up again. It has also gone through four coils which have been replaced. It has been serviced regularly but never shows any error codes. I don't want to take the car to Audi as I reported the problem to them when it was purchased at 6 months old and they said that because the problem was intermittent they couldn't help. I've been told it can't be the lambda sensor otherwise it would fail its MOT. Could it be the MAF sensor? I would really like to get to the bottom of the problem as its only done 45,000 miles and it is a lovely car to drive.

Asked on 10 November 2010 by Ian Schofield

Answered by Alan Ross

It may well be the MAF (mass air flow) sensor. Indications of a failing/failed MAF are poor idling, increased fuel consumption,missfire and or loss of power. They are quite costly to replace,so it may be worth checking it out first. It is possible to clean the surface of the sensor, by unplugging it and wiping it with 99% isopropyl alcohol, or a quality electrics cleaner. Remove the sensor from the housing and clean the element.If this improves the performance you may want to replace the sensor. Let me know if it works.

Tags: economy

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