odd chirp

[Rhino23]

So on my way home from work today I noticed an odd chirp sound coming from my truck, when I got home I popped the hood thinking it was a pully or the belt, It seems to be coming from the back side of the motor or underneath. It's a 1998 with a 4L V6 5 speed manual. My cousin is a mechanic, and he came by for a few to check it out, and he thinks it's the throw out bearing, but he's not positive, the chirp is kind of intermittent and does increase when the rpm's increase. Any idea's?

 

[Runnin'OnEmpty]

Is the noise more noticeable when listening from the right side
wheel well rather than the left side? If so, then I'd suspect the
chirp is coming from the cam position synchronizer. Do a search
and you'll find lots of info on fixing this. Replacement is not hard,
but access is limited.....

 

[Rhino23]

that's what I have thought it was but not sure, It's only happened one time other than the day I posted this.. I was told that it could also be the Throwout bearing, but I'm not sure on this either.... I'm just gonna wait till it happens more often then I'll take it in for a diagnostic.