random hiccups

[Bokerman]

I have 2018 1.6 GTS Levorg with 90 000 km few months now. I noticed that car sometimes does small hiccups while driving around town. It happens every few trips and when it happens, it is only once (only one time did it twice on short trip). Hiccup feels similar to hiccups my old car had when he had head gasket issues, but less pronounced. I think it is not head gasket as when im driving it on highway and push it hard sometimes it doesn't have same issues. Also i don't think that is CVT chain slip as i didn't noticed change in RPM when that happens.
When hiccup happens it is in low RPM (below 2000) with constant speed or maybe slight acceleration. Also i don't know if it is just coincidence but good number of hiccups happened on same place when im driving from work (few minutes since start of trip and on 1% uphill, speed around 60 Km/h .

I read somewhere that it could be torque converter locking/unlocking.

 

[Robsyuk]

Try replacing the cvt fluid and see if it resolves it.

 

[Bokerman]

It doesn't feel like it is transmission problem. More like something with fuel

 

[rnvb]

Have you tried a different (higher if possible) grade of fuel? Also maybe check the fuel pump, spark plugs etc. Is there any sound or jerking when it happens?

 

[Robsyuk]

It doesn't feel like it is transmission problem. More like something with fuel

I would have thought the engine would see a fuel issue via a sensor and give you the engine code.
Do put the highest obtain fuel you can find in it and and give it a good run.

I only use this booster.

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You could also clean the maf and make sure the spark plugs and coil packs are not loose.

 

[Bokerman]

I tried other fuel provider, but same grade and no change. I scanned with OBD but didn't get any noticeable error. I'm also driving with scanner on, but couldn't find any anomaly when hiccup happens. I mostly drive with MAF flow, fuel/air ration, and knock sensor (knock sensor registers knocks sometimes but i don't feel them and it seems it is not related to this hiccup). Also it seems that this happens only when i cold start car and when temp raises to 40-50 C. Also checked MAF sensor, but it is clean.
I want to scan differential and torque converter but couldn't find something like that in app.