Not Jimny related - question for mechanics

Morning all. Not a Jimny question, but just looking for any thoughts. The wife has a 208 GTi which has a 1.6 turbo unit, and although it generally drives fine, there is an issue when you put your foot down. Still under warranty, but dealer says they cannot find an issue (which to me means they plugged it in and nothing came up). Best way I can describe it, is it surges. When you accelerate hard, it is not a smooth power delivery, it feels like it comes in waves. Had numerous turbo motors before, never had an issue like this. Any thoughts on what might be the problem??
Cheers

Not going to be much help unfortunately, but start simple and inspect the entire air duct circuit within the turbo system. An air leak on both the input and output side of the turbo can impact the way it performs.
After this it gets more difficult, it could be anything!
I assume this surging is not normal for the GTI, any forums or Facebook pages with owners experience you can ask?
After this I can only think rolling road engine tune. These people have the equipment to look at the performance of the entire system and are likely to spot the issue, you may even get a few more bhp in the tune.
Good luck
Mike

Could be air flow monitoring related or vacuum/pressure control system related. Or it could just be because it is French and taking industrial action?

Doesn't seem to be a common issue on these, and looked at upping the BHP but seems they don't take kindly to it. Currently putting it down to French crap - she has had a couple of Fiat Punto turbos in the past, so we know sometimes to just overlook certain things!! Will have a look at the air pipes in the next few days.
Cheers

Try a Mass Air Flow sensor clean with some proper spray cleaner.
The dealer should have been able to see data from the sensor on their OBDII gear to see if it is acting up, but they may just want to get you to take it in when it eventually breaks down so they can charge you for replacing it.
(Cynical? Moi!)

You may well find there is nothing wrong with it.
My last two vans and both my son's vans do the same.
They drive as normal but the accelerator pedal has a bit of resistance 3/4 of the way down, when you press the pedal past the resistance the turbo kicks in, it's like a kick down switch.

Imagine you are entering a roundabout and miss-judged the traffic speed coming from the right and the engine has bogged down, you'd press the pedal down further than you normally would to get out of trouble this is where you'll the usefulness of this function especially in 2nd gear, and it can take you by surprise.

Most new diesel cars have this function.

Hi Jimx5 - the issue is with constant turbo, not just initial spool up. Foot on floor, let it go up through the revs, it is not a smooth power delivery. Feels like something (fuel starvation?) holding it back as it surges the power in and out.

Could the waste gate be opening?

I had a problem a few years ago with a diesel turbo, there was just a general lack of power and then all of a sudden a pop and almost no power at all. Turns out the hose came off the inter-cooler and then you get virtually no air in to the engine.

If it is not a sensor is it a loose pipe?

Think I need to do a check on all the pipes. Not sure about the waste gate, it is very quiet under operation so difficult to listen out for.