Originally Posted by Meulen

I'm having a similar issue. I installed FI HFC's and CBE. It's definitely misfiring. Light withing the first 100 miles. I don't drive the car much. My mechanic ran the diagnostic and it read "multiple misfires" He cleared the code and the problem went away. I suspect there is a lot of stuff burning off in the HFC's and CBE and the O2 sensors are trying to read things for the ECU to adjust to the new exhaust. My mechanic said to let the HFC's and CBE break in a bit and see if it throws the SES light again. But it seemed fine after he cleared the SES