Ruckeln/stuttern im stand und uphill! 323f BA

Hey, I’ve always had the feeling recently that when I’m still in the 3rd course and then start a certain climb, the car starts to stutter slightly… I didn’t think anything about it because I thought that it’s pretty sensitive to low speed… but it got worse, so I suddenly had to stutter at noon (about 28c in the shade) while riding uphill and the car didn’t want to speed up anymore… Luckily, there were new ones on the way anyway. The problem was still there… then drove home with a bad feeling … then saw that the Lufi box was not very dense, but not really open so then on occasion also sucked out the box. Since the bonnet was already open anyway, I thought, look at the spark plugs at once, yes well I thought they were a little rough black for my mack, but then found such comparison pictures in the net and they looked quite normal worn out and actually still in good condition. By the way, which spark plugs belong to the in the 323f BA 1,9l 114ps? What I somehow fear is that the Lambda probe is. Oh yes the exhaust (end pot), sounds like a tractor and wobbles quite in the stand… Would be very grateful for any helpful answer and apologize for any spelling errors the gach t were or should still be coming