gobbler87

Hey all,
I drive a '94 T100 4wd 3vze with a 5 speed manual transmission. I've been looking around at a lot of other threads on the site and have found solutions to similar issues, but nothing quite like what I'm experiencing. About a month ago I was cruising around 75 mph and noticed my speedometer started bouncing around erratically. This was accompanied by a screeching from under the hood (sounds like a bad belt, but I replaced those last summer and they looked fine when I checked them) as well as some hesitation in the engine. This only lasted for that one trip and then subsided until about a week ago and now it happens consistently. I know I should have looked into it more when it first started, but as a broke masters student, I find myself putting off maintenance issues until the last possible minute. I know this is terrible and I apologize for any tears I may have just caused for any of you. Anyway, the engine hesitation only happens, or I should say is only noticeable, at higher speeds (50+). But, the speedometer will bounce around for a few minutes and then go steady for a few, only to start bouncing again at all speeds. I've read where other guys have had issues with the speedometer bouncing and making noise caused by a bad sensor or cable, but no mention of any hesitation from the engine. Any suggestions? Thanks in advance for the help!