Hi guys, I've got a 1998 Z3 which has a weird misfire at idle. It feels absolutely fine while driving, but it vibrates at idle. It's been slowly getting worse, or at least more noticeable.  The revs at idle are at around 650rpm, which seems ok. If you stand by the exhaust pipe, you can hear it misfiring maybe once every few seconds though. What I've done so far: - New spark plugs - New PCV valve - Cleaned throttle body - Cleaned IAC valve - Visually checked for vacuum leaks