Awesome! Thank you very much!

It gave me errors number 13 and 34.. So lambda and intake air-flow sensors are damaged somehow.. Is there any way to even erase error memory without connecting to PC or other diagnostic tool?

If you remove the battery cables for 5 minutes that should clear the codes.
Of course once you start it again, if it senses a problem the light will come back on again.

Worked perfectly! My Buick told me error numbers 13 a 34.. So my lambda was dead (so I replaced it) and my MAF sensor doesn't work properly (ordered it and waiting)..

MAF acts weird, one time the service control light is on, sometimes it'* off.. It happens during the ride.. When the light is off, engine goes smoothly.. When it'* off, engine starts to push-pull while running "D" on idle and the idle itself is unstable too..

I'm going to replace MAF, change spark plugs and also their cables.. Thus solving the problem I hope..