Rmp's float, dipping

[Hopipola]

Hi all jazzers.
 I have a little bit of an issue with my jazz ge si 57000miles 2013. I own this car for a one year and now it starts floating rpms. Car has k&n filter and backbox delete, sensors hasn't been touched. Asked mechanic about it he seen exhaust he can't think of what could be the cause as sensors are intact. Before exhaust backbox delete i use to took out filter and cars rpms didn't dip to stall they where as supposed to be but now it stalls as you can see in video.

https://youtube.com/shorts/J8wyvoIOjoE?feature=share

But that's not the biggest issue just caught my attention.
When driving normally just after cold car light dissapears when in traffic and taking out from 1st gear it dips to 500rpm, rattles comes back, dips little higher then 500rpm but does it more when taking out from 1st gear, 10min later i tried to film it doesn't do it at all. Air Filter been cleaned 1month ago with oil applied. Any ideas would be much appreciated.
Thanks all

[nowster]

What's a "backbox delete"?

[MiniNinjaRob]

If there was no problem after the back box delete and air filter change then it shouldn’t be those at fault BUT I think it would be worth swapping the air filter back to the standard one to check if it solves the problem.

Other than that plugging in an OBD scanner and seeing what happens in the data when it stalls would be worthwhile. As a start maybe it is being starved of air or fuel when cold? Just a stab in the dark at present.

[MiniNinjaRob]

What's a "backbox delete"?

Not hard to figure out, I assume you know what an exhaust back box is and the meaning of the word delete? 😳😳🤣🙄

[nowster]

Oh! If you're removing the silencer from the exhaust, that's probably going to affect the back pressure and will put things out of balance.

I thought ricing up Honda Fits was something that only happened in the USA.

After that, should I now get a flat cap? 

[Hopipola]

It started not after backbox delete. Maybe rpms were little bit floating but there was days and random times when it dipped almost to stall an engine. Weirdly oil level light came up. It was for oil change i topped it up like 200ml like just perfect where it should be on dipstick and now rpms doesn't float. A bit of a mistery.
Again i have car for a year now, came with k&n filter, backbox delete was done 2 months ago, everything was fine, just a little dips, flows but now there was like two days it dipped to almost stalling the engine.

[Jocko]

Weirdly oil level light came up.

It is not an oil-level light. It indicates low engine oil pressure.

[MaV]

I heard the oil of those air filters can mess up the mass airflow sensor.
Not sure this is you're problem but it could explain at least some of the symptoms.