OJazem; I'm not familiar at all with Skoda, but.... If the Skoda engine uses VVT (variable valve timing) it could very well be the problem. Too heavy of an oil can cause sluggishness because the VVT can't change as needed. A good quality (synthetic, if the manufacturer suggests) 5W30 would be good. Modern cars are designed to run thinner viscosity oils than we are used to. It will also help fuel economy.
Let us know if you still have stalling issues afterwards. There are other possibilities for that.
I own Skoda octavia 2001 2.0. since last month, engine keeps stalling:
1) while driving (for 10km or sometimes for 1 - 2 km in distance).
2) or keeping the car idle for 20 - 35 minutes.
and when it stalls, It cranks but does not fireup. unless, waiting for 10 - 15 minutes.
1) when I am driving (over 60km in speed), I feel like the engine is holding back and loosing power. As soon as I accelerate, it powers back (or lets say looks like gaining power to run again) and runs smoothly. This happenes, in couple of seconds (like 1 - 2 seconds.). If I don't accelerate, engine goes off.
2) sometimes I drive for 4 hours without having this issue (this is rare other than having the engine stalls twice everyday).
Things I have done so far:
1) I have changed the battery since it was kinda old.
2) got the car scanned (no issues or fault were found).
This happens since I changed the engine oil ( type 20w50 ) I read on the manual and found the car oil type is 5w30. would the different type of oil would make the car behave like this?