My driver's side door has made a popping noise whenever you open or close it. It's been doing it for months, I always thought it needed to be lubed up. I finally got around to lubing it and it did nothing. Upon inspection, I noticed that the nuts holding the door tension had backed out. Tightened them (10mm) and it was good to go. Looks like Toyota used a thread locker on them but apparently that did no good. Don't have any lock-tite at the moment so I'll have to revisit them when I get some.