Annoying low revs power issue

[Timbo]

Hi,

I've had my 07 2.0 170 SE for about 2 months now and I am generally pleased with it. However, I have an annoying low revs power issue that I'm trying to sort out with the garage I bought it from.

At low revs (between 1500 - 2000), and when accelerating gently, the car feels like it's pausing, like you've taken your foot off the accelerator, then starts to pull again. My wife describes it as if it's "missing" temporarily, but only at those low revs. It's most noticeable if you're trundling along in a queue of traffic at constant revs (say 1500 revs at 30 mph), then try to accelerate, it starts to pull away, pauses, then goes again. It's as if something is sticking. If you accelerate more quickly/rapidly then it's not noticeable.

I've had it back to the garage last week (as the engine management light came on and it entered limp mode, which cleared by switching the engine off then on again), and mentioned this as well. They scanned it with a Snap On box, which came up with a Turbo Overboost code, and said it was probably a loose air pipe, and proceeded to tighten all the jubilee clips around the turbo and intercooler. The limp mode fault hasn't reoccurred (having run it on a 400 mile round trip last week), but this acceleration problem persists.

Can anyone suggest anything that I could take back to the garage as a suggestion instead of being fobbed off with an "I don't know mate, these intermittent faults are too difficult to diagnose" situation?

Thanks everyone.

[arman123]

first i will get the car scanned using vcds see if your getting any codes and second change the maf buy a genuine one from dealer

[zollaf]

you have bought it from a used car dealer then. give him the opportunity to fix it and if he can't, take it to vw and get then to fix it and send the seller the bill.

[Timbo]

Ok, took it back to the garage today. They plugged it into a Snap On reader which came up with no fault codes. So they cleaned the MAF and emptied a bottle of Wurth Injector cleaner into the tank to see if that made any difference.

Unfortunately, after about 30 miles on the way home the engine management light came on again and the turbo cut out (it's about 3 weeks since this last happened, and again it cleared by switching the engine off/on). The last time it did this it came up with a Turbo Overboost fault code and the garage tightened all the air hoses.

The garage now want the car in for a couple of days to try and solve the issue, however, I'm a little concerned that the code reader they are using isn't going to pick up all the relevant information, so I'm considering getting it scanned myself before I take it.

Is there a database of VCDS operatives anywhere, or can anyone recommend someone in the N Devon/N Somerset area that has the equipment, or should I book it into the local Audi dealership? If anyone can give me an idea of cost I'd also be very grateful.

Thanks everyone.

[slippyr4]

VCDS - Users Locations

[dazza291970]

Was it definitely an overboost code?
The symptoms sound identical to a problem I had which was P0299 Underboost problem. Mine also a 170bhp TDI.

Car would randomly enter limp mode, particularly when trying to accelerate on motorway.

On mine it was a leaking vacuum actuator for inlet manifold flap.

£12 part and coupe of hours to do if you are happy to take take inlet manifold off.
Once fixed car ran smooth and former power was restored!

[zollaf]

a snap on code reader should find it, depending on which code reader it is. i use a snap on modis which is as good if not better than vcds.

[Timbo]

Was it definitely an overboost code?
The symptoms sound identical to a problem I had which was P0299 Underboost problem. Mine also a 170bhp TDI.

Car would randomly enter limp mode, particularly when trying to accelerate on motorway.

On mine it was a leaking vacuum actuator for inlet manifold flap.

£12 part and coupe of hours to do if you are happy to take take inlet manifold off.
Once fixed car ran smooth and former power was restored!

Spooky!

Just back from the Audi garage in town who has diagnosed a fault with the same part. Spoken to the garage who sold me the car (which is 40 miles away and who have had it back twice already to look at), and they said to book it into the main dealer and they'll pick up the bill.

Result!!

[anthonytutton]

Was it definitely an overboost code?
The symptoms sound identical to a problem I had which was P0299 Underboost problem. Mine also a 170bhp TDI.

Car would randomly enter limp mode, particularly when trying to accelerate on motorway.

On mine it was a leaking vacuum actuator for inlet manifold flap.

£12 part and coupe of hours to do if you are happy to take take inlet manifold off.
Once fixed car ran smooth and former power was restored!

Hi Mate, I've got exactly same issue with my 170bhp. I suspected a leaking vacuum pipe for a while. Do you have any more info regarding the vac actuator that you replaced? part number etc? where you bought it from?
It would help me alot to get this fixed on mine!

[Timbo]

Had the inlet manifold vacuum actuator changed a week or so ago and it is a lot better, an awful lot better, but still not quite right!

Although no engine management light/limp mode episodes, and the car accelerates a lot better at low revs, it still seems to hesitate very slightly and the engine sometimes "hunts" at tickover, somewhere between 900/1000 revs.

I know it can be very difficult to pin down an exact cause, and things are a lot better than they were, but is there anything obvious I could check (pipes/hoses etc) that would save me some time, rather than just blindly ask the main dealer to take another look?

Thanks again, TT