lexx426

So i put in a y pipe a few months ago and afterward my ses went on. It read knock sensor, so i replaced that. It was still on afterward so i kinda didnt think about it. I realized though that i need to pass smog and register by the 2nd of febuary... Straight to business i went. In the last few days i changed the spark plugs, changed my o2 sensor (code said it was o2) and fixed my leak in the y pipe. I dont get it though, it came on again today. It was dark so i couldnt check the code but im confused.

What else can it be? My car studers sometimes at idle. Kinda uneven feeling, and up to 3k rpm the accelaration feels uneven and wiierd. Does anyone have any sugestions?