I just changed the knock sensor and O2 sensor on KA24DE on my 1995 S14. For the knock sensor replacement I had to remove the coolant line and surrounding ones out the way and the intake to be able to get it back in place. After that I changed the O2 sensor. The first time I drove it after the changing both of them it was well and no issues at all. Then second time it started to shake a lot when stopped like the exhaust was just sending pulses instead of being a steady flow, and I hear a whistling as well. I wonder if anyone can give any advice with this issue.