Jumpy A4 TDi

[RickH]

Some advice if can please people, before I go phoning the garages for their best sucking of the teeth.

05 (2005) A4 2.0 TDi saloon with full service history. 40k miles and no problems as such. I've now noticed a sort of kangarooing at higher revs when I put my foot down to overtake. It only seems to happen in 3rd and above. No problems off the line in 1st or 2nd. My initial thoughts are the fuel that I bought froma brand new A**A forecourt, rather than the more expensive clutch that it could have been. Cruising at 8leptons on the motorway is no problem, its just if I try to overtake and put the foot down. No excessive smoke either.

Would anyone suggest getting an injector cleaner from Halfrauds? Would it be best to try this before, or after this tank of fuel?

RickH

[Tame Technician]

If when you say jumping you mean a misfire, sounds like a fuel pressure issue, try it a full throtle up a hill in 3rd, try to take it to the red line, does it get there, is does it run out of puff at around 4000-4200rpm with a misfire. If it does clamp the return fuel line near the filter with some mole grips or similar and repeat the test. If the car is then fine (with artificially high fuel pressure) it is like you need injector seals for the PD injector units. Although it can be the tandem pump on the back of the head.

This is very common on the PD deisel engines.

[RickH]

Will try that test when there's slightly less frost/ice around. It's a bit cold up here round Glasgow.

So if it is like you think, injector seals. Is that (a) and expensive fix, (b) something I can do? I imagine the parts are going to be peanuts, but if I take it in, then it's going to be labour rates that cost the most.

As for the alternative, 'tandem pump', whatever one of them is. Please explain the scenario.

RickH (pistonhead yes, knowing the ins and outs of A4 TDis, no!)

[RickH]

Problem gone (for the moment). I think I'm going to see if its the tank of fuel for the minute. Its the cheaper option at least.

RickH