removed ALL my emissions controls a few months ago and car loved it and ran great. didnt lose any gas mileage and now my engine looks great but now all of a sudden i got a ton of knock at high rpm. hitting as much as 8 with fuel trims in the +2 to -2 range. everything on the scanner looks exactly the same as it has for the past ffew months except for this knock. im kinda thinking the cat may be to blame as its the only thing left and i have no exhaust leaks but dont know what the signs of a bad cat is. can anyone tell me of shot me other ideas of what it may be. oh and reduced my timing by 2.5 degrees and still getting 5 on the knock sensor. im scared to go fast now. im so confused
