Well, ruled out the TPS possibility...reads 0.972 throttle closed and 4.71 WOT. Smooth transition throughout the voltage range with no flat spots. Right on where it should be.

 

Well, I have the same dang problem with my 94 (302) I went to the dealership and spoke to the guys and found that the catalytic converter is bad and the "buzzing noise" is the backpressure running up the tube to the check valve and or noise transferring through the bellhousing. They said it's hard to detect but is more than likely the problem if the computer is throwing no codes or throwing code 33 without the check engine light on. You can also see if the cats are bad by observing the temp guage...if the vehicle has always run cool through intense summer driving and then runs hotter in cold winter months. This shows that the engine is running increasingly harder to get exhaust gas out causing coolant temp to increase. They also said that if you put the engine under load (WOT) and hear the buzz/rattle in the #4 cylinder location near the firewall and cannot get out of your own way then the #1 cat (the first one with bot downpipes running into it) is clogged and needs to be replaced. This is caused by short trip driving and not allowing the cat to get to full operating temperature and shutting it off allowing the cat to fill with moisture which ultimately destroys the ceramic. The solution...a freakin 1520.00 oe y-pipe with cats. Hah! I bought the 190.00 Catco set-up and laughed at them fools. Check it out to see if it is you catalytic converter, that is if your check engine light is not on. Good luck!