Hickup when accelerating.

[David021]

Hello. My Audi has a "hickup" where the engine cuts out for a split second , it does it only one or twice at around 3.000 RPM, at 4.000 or above it's more frequent and it doesn't happen all the time. Not lights on the dash, nothing shows up on VCDS scan , the oxygen sensor was changed recently as well as the injectors with new o-rings. 

Any ideas what could it be?  

Edited April 27 by David021

[KevinAudi80]

Hiccups or erratic engine operation at certain RPMs can be caused by problems with the ignition system or fuel system. Ignition misfire or erratic fuel delivery can cause unstable engine operation. Additionally, if the fuel injectors are contaminated or damaged, this can lead to erratic fuel delivery to the engine, affecting engine operation at certain rpm. I would also consider damage to the exhaust system, such as leaks, holes or damage to the muffler, can affect engine performance under certain conditions, including at certain rpm, or damaged or malfunctioning sensors, such as the crankshaft position sensor (CKP) or throttle pedal position sensor (TPS), can affect engine performance under certain conditions.

[Steve Q]

Could it also be an issue with the turbo if it's not kicking in? 

[David021]

23 hours ago, KevinAudi80 said:

Hiccups or erratic engine operation at certain RPMs can be caused by problems with the ignition system or fuel system. Ignition misfire or erratic fuel delivery can cause unstable engine operation. Additionally, if the fuel injectors are contaminated or damaged, this can lead to erratic fuel delivery to the engine, affecting engine operation at certain rpm. I would also consider damage to the exhaust system, such as leaks, holes or damage to the muffler, can affect engine performance under certain conditions, including at certain rpm, or damaged or malfunctioning sensors, such as the crankshaft position sensor (CKP) or throttle pedal position sensor (TPS), can affect engine performance under certain conditions.

As I mentioned, the injectors were changed with brand new ones maybe 3.000 kms ago so I do not think that they are contaminated. I have a rubber clamping at the muffler which is worned out, so the muffler moves a bit, sometimes I can hear it clanking , I will need to change that, but I don't think it should not cause an issue like this. 

But good news, as I was driving it a little bit harder maybe a week ago, accelerating all the way through first , second, third and fourth, I did this maybe three times and the problem dissappeared. So maybe something was clogged up or was not functioning as it should. It seems like a little bit of hard driving solved this issue. 

[David021]

21 hours ago, Steve Q said:

Could it also be an issue with the turbo if it's not kicking in? 

I don't think so, the car accelerates normally as it should , it has all it's power. It doesn't seem like any power is missing. 

[David021]

Update: It still does it sometimes , not always and not that often as before, but now it can happen even at lower RPM-s. 2000 or 2500 , mostly in second and third gear.

I still can't figure it out what could it be. 

Edited May 10 by David021

[David021]

Turns out it was a faulty throttle body. I took it out and cleaned it, seems like the problem temporarily disappeared. 🙂