Clutch Problem
 

Alrighty, so here it is, I have a 2000 4Runner, completely stock: I'll step on the gas (usually to pass, so b/w 2000-2500 rpm) and the truck will continue accelerating at a relatively steady pace (on occasion it will stop accelerating), however, the rpm's will go up like I'm just sitting there in neutral revving the engine. This is very noticeable in 4th and 5th gear, never in 1st, and very rarely in 2nd and 3rd. As far as I know, the guy who owned it before me didn't have to put a new clutch in it, and I definetly haven't (yet), so it's been running on this clutch for about 176,000 kms, so it's got some wear on it. My guess is that the clutch is starting to slip, and it's about time for a new one. What do you guys think?

sounds like slip. Does it smell like anything after this happens?

Nope, doesn't seem to smell like it's burning, or at least not that I noticed.