Hesitant Gas Acceptance: Causes & Solutions

Hi fellow DIY enthusiasts,

I'm having a problem with my Seat Ibiza, 110 horsepower, AFN engine.
The engine now has 110,000 km on it, and for the past 3,000 km, it's been misfiring.
It's performing poorly. The error occurs sporadically, regardless of whether the engine is warm or cold. When driving at a leisurely pace on the highway, around 120 km/h, it accelerates well in direct gear. So far, I've only noticed that the error always occurs when I'm driving aggressively.
Rapidly switching between the brake and accelerator. Then, for about 1-2 seconds, there is no power at all, and after that, you can feel it smoothly revving up again.
So far, I've only checked the brake switch on the pedal, but that wasn't the problem. The values from the accelerator pedal sensor are also okay. What else could it be? Maybe someone here has an idea; that would be great.

Sure, here's the translation:

'Thanks in advance, Daniel.'

Hmm, I would have also guessed it was a brake pedal switch.

Is the new switch properly configured?

What does the error memory say?

CU Gremlin.

Unfortunately, there's nothing in the error memory.

'I actually downloaded a repair manual for that switch, even though I didn't really need it. But if it's installed correctly, it will be recognized perfectly. And I've checked all the wires and connectors; everything is fine.'

Could it be that the engine control unit (ECU) reacts too slowly when there's a quick transition between the accelerator and the brake pedal? Then, the DME (Engine Management System) simply cuts off the fuel supply via the pump, and nothing happens anymore?

g1om wrote:

So far, I've only been able to determine that the error always occurs when I heat it properly. Rapidly switching between the brake and accelerator. Then, for about 1-2 seconds, there is no power at all, and after that, you can feel it smoothly revving up again. So far, I have only checked the brake switch on the pedal, but it wasn't the problem.

Hi Daniel,

The symptoms are reminding me (again, in part) of my stuck VTG.

Can you monitor the boost pressure (using LDA or VAGCOM)?

I have a VAG Com, but unfortunately, it's only available as a fixed computer in my workshop. Would the VAG Com even be able to record data for such short periods?
Besides that, an LDA would also be quite slow at the moment, right? You need to give me a little help.
In what range should the boost pressure be ? Unfortunately, I'm still not really understanding the information from the specification sheet. Please try to explain it to me.

Hi,
It's not that difficult, really.
Take a commercially available pressure gauge with a measuring range of 0 to 1.5 bar and connect it to the pressure side of the intercooler system.
When accelerating suddenly, pressure spikes up to 1.3 bar are normal. The system is regulated to maintain a pressure of 1 bar above atmospheric pressure.

Best regards, Andy.

Okay, so I installed a nano chip today, and the jerking/power loss issue still occurred during a test drive. Unfortunately, nothing unusual was detected on the nice gauge. The boost pressure builds up cleanly and is within the acceptable range. I also went to Seat today, and they suspect it might be the fuel pump, specifically the fuel pressure regulator.
It's possible that the issue only occurs during the drive and not when the ignition is turned on for a short check. What are your thoughts on this?

g1om wrote:

Today, I also went to Seat, and they think it might be the pump, the control panel! It would be possible, as the error doesn't occur during the drive, but only appears briefly when the ignition is turned on. What do you think about that?

Hmm...

If the control panel were to jam during travel, despite the engine vibrations, then it's even more important to check it occasionally when starting the engine and with the engine idling.
-> It should actually provide a more frequent flashing indicator light, because the pump, being the heart of the system, is checked very thoroughly.

Right now, I'm thinking more about the NBF (Neutral Balance Factor) -> knock test at approximately 3000 rpm.

Hmmmm... how do I check the NBF?

The individual values between the cylinders are within the tolerance range, but I don't think that's very significant because the range itself is quite small.
I've adjusted the engine so that it now triggers this error at 2500 RPM, and while doing so, it doesn't stall, and the light doesn't really illuminate .
Especially when I'm on the train, it's just not fun because I always have this problem that I didn't have before.

I've really tried a lot of things already, but nothing has helped.

I will definitely continue searching.