I am getting a squeaking noise coming from the passenger side seat. It doesn't happen all the time, but enough to bother me. Has anybody else had this kind of problem? If so how did you fix it? Any suggestions.

BTW I check all the bolts that hold the seat and they are tight. I even shock the seat hard to see if I can make the noise again, it didn't happen.

 

Another observation, I even heard the same noise when my friend was sitting in the seat while driving. Any ideas???