Hiccuping and surging power

[Munchies 06]

Heya guys new to the forum and I can see there is plenty of help on here! So I need some lol.
So my 2004 cupra r decides that sometimes when I boot it through the gears or drop it from third to second and put my foot down to completely loose power for a split second. And if I keep my foot planted it just hiccups for a few seconds before it puts the power down. It’s not the traction control as it does it if this is on or off. This can happen in any gear with my foot planted. Any ideas? It’s been on a rolling road yesterday and done over 50 miles on it and it didn’t happen once!! I’m guessing because it wasn’t under the same kind of load as it is on the road?
I’ve replaced the following with all genuine parts one at a time and it still does it. Only second hand part I tried was a few n75 valves. It’s only an intermediate fault which is even more annoying but it does happen on every drive at least once!
No fault codes come up.

N75 valve ( tried 2 second hand ones)
N249 was deleted before I got the car so it’s not that
Plugs
Coils r8
Maf sensor
Injectors
Dv

Tomorrow I’m changing the pre cat lambda sensor to try that.

Anyone else had this issue? Please help me before I smash this car to bits

 

[liamlayson]

Still having this issue mate?
Does it judder when full throttle as if it’s trying to build boost but releasing the pressure straight away?

 

[Munchies 06]

Still having this issue mate?
Does it judder when full throttle as if it’s trying to build boost but releasing the pressure straight away?

Still got the issue mate yeah. I’m truly confused
yes mate it does do that. Also does it in any gear at anytime if I’m on full throttle. It’s doing my nut in

 

[Munchies 06]

Still having this issue mate?
Does it judder when full throttle as if it’s trying to build boost but releasing the pressure straight away?

Any ideas? It doesn’t do it all the time that the worst bit. I can really boot it through all the gears and it’s fine. Slow down and do it again and it happens. Might even be ok for a couple hours then just when it knows I’m in a good mode it decides to do it just to ruin my day

 

[iammooks]

Have you checked your boost pipes?

I've got a diesel, so slightly different, but I had similar problems a couple of years ago and it turned out a garage had tried to refit a broken horseshoe clip and it had popped free. It wasn't completely disconnected, so it could still build up some boost, but it was hesitating and surging.


Sent from my iPhone using Tapatalk