Folks, Still working on solving the misfire/studder on my '86 22re. I'm using a NWOR header (please don't flame as it's been on for years) and it uses the #2 cylinder tube for the O2 bung... I know stock manifolds used combo #1 and #2 cylinder for the O2 sensor to operate off of. Do you think with the O2 sensor only sensing one cylinder could confuse the ECU and produce this type of side effect? One other thing I've tried is directly tied a vacuum line to the fuel pressure regulator (thus producing higher pressure to the injectors) This seems to mitigate the miss but doesn't cure it. <img src="/forums/images/graemlins/confused.gif" alt="" />