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I gave my car a little raz the other day obviously on a private road , i was in 4th gear and at about 5500 rpm it lost power then cut back in and out again all the way to 7000 rpm then did the same in 5th gear at the same revs.

In all the other gears it revs cleanly all the way up to the limiter.

Any ideas what this could be?

Don't go above 5500 revs

Sorry thats not helping,I'm sure someone will be along soon to help.

Probably sucked in some passing pedestrians at those revs

... sorry, I'm not much use either...

TDI's are always like that
(I'll get my coat)

carlosfandango wrote:I gave my car a little raz the other day obviously on a private road , i was in 4th gear and at about 5500 rpm it lost power then cut back in and out again all the way to 7000 rpm then did the same in 5th gear at the same revs.

In all the other gears it revs cleanly all the way up to the limiter.

Any ideas what this could be?

Could well be overboost cut-out - (Boost Leak)

Those dam pedestrians and their dogs they always mess up my air filters!

Yes could be a boost leak or a faulty sensor i guess.

I had the same problem, mine was due to a faulty exhaust sensor (lambda probe) and the other one, sounds silly but it was the problem but as Norrs says could be a boost leak as that is what i initially thought. Get it Vag com'd. Good Luck.

p.s mine used to do it at around 3rd or 4th gear at about 100 mph (on a private road somewhere)

Thats what was happening with me, well pretty much.
I had a burst tbb, had split right along the underside of the tb side jub clip.
Id definately get boost leak tested. Was also told once i fixed it to disconnect the n75 til i got it checked out properly.
i didint get it checked out on time and one of the turbos siezed...

Surely, if it was overboost the car would drop into limp home mode and lack any power (comparatively) ... it wouldn't come back and go off?

Check out the fault codes with VAgcom if yo ucan.

Paul

VAGcom show 2 faults both with exhaust sensors, got them on order so should fix the problem. Thanks to Kim at QST for his prompt attention as always.

I have had similar problems a few times, at first it was the MAF, then it came back so i changed out the DV (i have done this twice so i have decided to go for forge units as you can maintain them opposed to just having to buy new ones as with the OEM units), happend again so i changed out the plugs, while changing out the plugs i noticed quite a bit of scorching around one of the coil packs so i replace that also, the car is now runing fine although i have an N75 on order as i might aswell change it as i have changed everthing else anyway.

Hope this helps

Andy

I had an N75 on a 1.8T 190 B6 A4 that was faulty.
Symptoms were similar as you initially got too much boost (felt like an RS4!) then the ECU took over and cut it back.
Not sure there was a fault logged.
I'd be surprised if EGTs were causing this as from experience the ECU restricts boost all the time for protection when they are faulty but worth changing anyway if a fault has been logged.

If both your EGT sensors are on their way out, I'd be having a good shufty at your MAF- if its a few years old it could be causing you to run lean/overheat and screw up your EGT sensors.....

Cheers
Steve

OK I had the exhaust sensors changed and new plugs, but it is still doing the same thing, it had a new maf a few months ago but we popped a new one on just to see if it made a difference but it didnt.

The car doesnt have a boost leak as far as we can tell, I was wondering if it could be a fuel problem, has anyone had this problem with a fuel filter?
I had a bosh fuel pump fitted a few months back and it is very noisy maybe it could be that?