2005 RX330, owned since new 200-K miles. VSC and chi eng light came on, and when shifting to reverse out of garage it bogged almost stalling running rough. Got OBD reader and P0304, cylinder 4 misfire. I put new air cleaner in, cleaned throttle body, MAF sensor, replaced center front#4 cylinder coil pack and still happening? The flex hose sections from air box to throttle body don't appear to have any cracks or problems, engine mounts seem intact while putting into reverse, no drastic engine movement. I did first timing belt sac @115-K and plugs, PVC @ 131-K. any ideas as to what I should look at? Thx