My 99 ls400 was idling ruff, the scan tool found a misfire code for cylinder #8. A code for o2 sensor bank 1 sensor 1 and a code indicating there was bank vvti solenoid. Replaced vvti solenoids. Upon starting the engine there was awful tapping. I shut it down, And made a decision couldn't see any external reason for the noise, I scanned for trouble code there were none. Did a bad vvti solenoid set the codes. Any knowledge would be appreciated