my '86 IROC camaro started a slight rattle which has now turned into a more definite rattle when I am starting out in first, while the rpm drops as I let the clutch out, and then again when i near the redline, only today it started interfering with power however, i've noticed a major decrease in power, I thought it might be a worn U-joint and if so, it might not be too hopeless, but i don't really know what else it could be, any thoughts?