A4 2004 1.9TDi (130) Auto - poor mpg - help!!!!

[and_007]

I have just purchased the A4 1.9TDi (130) Auto, after 6 days of running I manually calculated the MPG at a wallet busting 37.7, used 15 gallons of diesel to do 582 miles.

After reading through the forums decided to get a full service done, have MAF sensor replaced and Engine temp sensor replaced, yet the MPG has not shown any improvement. I have also had diagnostics done which did not throw up any errors.

Al low revs (1100-1900) the car runs unevenly and revs can rise every 3 seconds by upto 200 rpm and then reduce back to the original level (just asthough the clutch is being depressed then lifted again), I can't help but think that the poor mpg and this are in someway related.

Does anyone please have any advice on what to try next,

thanks in advance for your replies

Andrew

[and_007]

I have sorted the MPG problem, although I am still getting the issue woth fluctuating revs up to 1,900rpm, this only happens when the engine is up to temperature. Anybody have any ideas?

Many thanks

Andrew

[cruiser647]

What was the MPG problem?

Have you had the car plugged in to VAG-Com for code reading?

[and_007]

MPG now sorted, getting 46-48mpg, still would like to see the increase as I do 30k per year, especially with the cost of a tank of fuel being almost a mortgage payment.

Still getting the rev fluctuation though, had it put on diagnostics no errors are being thrown up.

I am considering a remap, any advice.

[PetrolDave]

I am considering a remap, any advice.

Get the rev fluctuation problem sorted before you have the remap done. The remap will likely accentaute any problems that exist.

[TiSwAs]

Faulty EGR valve can cause bad MPG - check to see if it's weeping oil.

[and_007]

Thank you, MPG now sorted (getting about 47 to gallon), would like any advice on rev fluctuation though, just to remind you;

On a A4 (B6) 1.9tdi (130) auto, at revs up to 1,900 the revs fluctuate, when gradually increasing speed or maintaining a steady speed the revs can 'bounce by up to 200rpm), also on pull off get a judder when pulling off steadily, if I floor it I get great power delivery with no fluctuation or judder. The solution I have found to date is running in sport mode but the judder is worse on pull off (obviously), but beacuase it changes gear at higher revs I do not get the fluctuation in revs. Again all this onoy happens when the engine is warm, NOT when cold, I can't help but feeel that it is a sensor somewhere (I have already had the MAF & Enging Temp sensors replaced)

I REALLY would like to find a solution to this prior to getting the ECU re-mapped (as per previous advice).

Many thanks

Andrew

Edited May 20, 2010 by and_007
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