Low fuel pressure

[The Hedge]

Hi to all A4 gurus......

The emission control warning light comes on occasionally on my car, which is a 54 plate A4 2.0T FSi Quattro. I have noticed that the mpg drops off by on average 4 to 5 mpg when this happens.

Today I took the car out on a run. When I set out the light was on and according to the computer the car was doing only around 30mpg at 70mph in 6th. After some miles the mpg indication rose steadily to around 37mpg at 70mph, though the light stayed on (I assume it does not reset until the ignition is switched off). On the return journey the light was off and stayed off.

Having only had the car a month or so, I'm not 100% certain whether there is a loss of power when the light is on - perhaps power does decrease a little, but I rarely use anything like the BHP available.

A couple of weeks ago my garage diagnosed the problem as low fuel pressure, but were unable to locate the actual source of the problem as it is intermittent.

There is one other issue I have - trying to get petrol into the tank. The petrol pump keeps switching off and it takes an age to get the tank filled. Is this a general issue with A4's (I never had any problem with my last car, an A6) or is the tank vent likely to be blocked?

Any advice would be appreciated.

TIA.

[The Hedge]

WOT NO GURUS?

Obviously I have an obscure fault on this vehicle.

It's now booked in for another look early next week, so I'll report any findings in due course.

[Crasher]

What fault code did they get?

[The Hedge]

Fault code - sorry can't remember. The tech said it related to low fuel pressure and he hadn't been able to pin it down any more than that. It's not a problem and I can wait until next week. It probably won't be sorted then if it is still intermittent - we really need to catch it when the fault is active and that could be anytime.

[The Hedge]

This problem is still unresolved as my garage was still unable to find anything wrong even though I delivered it to them with the emission control light on. I think it may be some form of blockage / venting issue, especially with the problem of actually getting fuel into the tank.

My garage says that it could be the fuel pump, but at £173 + VAT + fitting it is an expensive item if it is not going to resolve the issue.

[Crasher]

Ask them for the fault code number.