('95 302) Truck is quiet at idle but makes a loud squeak-squeak-squeak-squeak at 1500+ rpm. Can't tell if it's idler, tensioner or alternator but it's charging fine.

Can't afford to throw money at it right now and I used the hose-stethoscope trick to no avail.

Can it be all three? One more likely?

 

Mine was doing it after I changed out my belt. Thought it was the belt so returned it and got a goodyear belt. Still made the noise so replaced the idler pulley. Now it still makes it! I'm going to replace the tensioner next, hopefully after I fix the door handle, gas gauge, bed bolts....