19 GTI bucking under low load

[mikecard1346]

Hi everyone, first post here but have read and learned so much from everyone thus far!

I've owned my car from new and have done oil changes between 5-7k miles, and use 93 top tier fuel. Stock tune with the only modification being a tcr axle back exhaust. I'm experiencing a noticeable bucking or what seems like a misfire for a few seconds while driving in 6th gear around 58-60 mph coming down from the crest of a small hill. This also happens on flat ground rolling along at about 3-5% throttle around 1500rpm. This is much more pronounced with the ac on and goes away if I get into the throttle a tad more. For those in MA this is most consistently occurring on route 1 where there are small rolling hills. It's been in the high 80's and into the 90's so this could play a roll but there seems to be an underlying problem I'm looking to track down.

There are no codes stored which makes me a bit hesitant to bring it to the dealer even though its under warranty. My local dealer is notorious for giving the "there are no codes so there's nothing wrong" or "your exhaust is causing that and we don't cover it". Looking at threads it looks like it could be a diverter valve problem but I'm not in boost at all when this happens.

Appreciate the help everyone!

 

[Diggs24]

You didn't give us any information, like is it DSG or manual or tuned or....anything. Sounds like you have at least an exhaust? What else?

 

[mikecard1346]

You didn't give us any information, like is it DSG or manual or tuned or....anything. Sounds like you have at least an exhaust? What else?

Just updated bro

 

[kyLman]

So I cant say from VW experience, but usually when there's a little stumble at a certain RPM/speed range...its a vacuum leak or something similar.
Might be worth smoke testing the engine bay

hopefully someone with experience can chime in

 

[OceanJack]

Sounds like a problem I had a while back, my issue was the LPFP.

 

[GTIfan99]

How many miles on it?

 

[Jose_Gti]

Manual transmission or DSG? Could be bad gas?

 

[tmw2442]

Low rpm stumbling and no codes, no CEL. I would go with carbon build up in that case. I wouldn't worry about the TCR exhaust...most dealerships/services managers don't know the product well enough to spot the change.

Do you have the ability to go an vagcom or odb 11 logging?

 

[JC_451]

You're probably just lugging it.

 

[TheJokker]

Yeah; sounds like lugging.

Think of the power band of your care as between 2,000 rpm and up. You never want to accelerate, even slight or mild acceleration, unless you are in that power band. Lugging occurs when you try and accelerate under 2,000 rpm's. It's very hard on your clutch. The only time you want to be driving at 1,500 rpm is if you are cruising at a steady speed. if you need to accelerate even slightly you need to downshift so you are back at or over 2,000 rpm.

Habitual lugging leads to fried clutches...

 

[mikecard1346]

How many miles on it?

23k

 

[mikecard1346]

How many miles on it?

Yeah; sounds like lugging.

Think of the power band of your care as between 2,000 rpm and up. You never want to accelerate, even slight or mild acceleration, unless you are in that power band. Lugging occurs when you try and accelerate under 2,000 rpm's. It's very hard on your clutch. The only time you want to be driving at 1,500 rpm is if you are cruising at a steady speed. if you need to accelerate even slightly you need to downshift so you are back at or over 2,000 rpm.

Habitual lugging leads to fried clutches...

Appreciate the reply. It occurred going down a slight hill while not accelerating or leaning into the pedal so I think lugging is out of the question. Been either riding or driving manuals for over 10 years and can feel when the car needs an up shift. I never get into the throttle under 2,500rpm and always roll on it as I'm aware these clutches are notoriously weak.

 

[mikecard1346]

Still trying to track down the issue, thanks for the insight so far! Might just have to take it in since I have plenty of warranty.

 

[mikecard1346]

Low rpm stumbling and no codes, no CEL. I would go with carbon build up in that case. I wouldn't worry about the TCR exhaust...most dealerships/services managers don't know the product well enough to spot the change.

Do you have the ability to go an vagcom or odb 11 logging?

I have a pretty high end code reader I can see live values with but no vagcom or obd11. What values would you be checking out of curiosity?

 

[JC_451]

You can lug the engine off throttle.

Start with simple thinking first.

Guaranteed, if you take this car in with no codes and they can't reproduce what you're experiencing you're just going to be out the diagnostic fee and receive zero satisfaction.