Hi guys-

I've lately been getting a very loud squealing sound after I push down on the accelerator (engine on). Not when just sitting idling, or when moving but with the clutch in, not when moving in gear but not accelerating, but only when I push the accelerator. Loud enough that people a block away turn their heads.

At first, it would quit after about 30 seconds, so I paid it no mind. And it's intermittent- might happen today, might not for a few days.

Seems to be getting worse, so now I'm thinking something needs to be looked at.

It stops squealing momentarily if I ease off the gas, but then starts squealing when I subsequently press down on the gas. It also seems to go away once I get into 4th gear (at about 40-45 mph).

If this is a belt making the noise, which belt is it? How do I go about confirming that it is a certain belt making the noise?

Does this mean a belt has gotten worn enough to need replacing, or something just needs to be adjusted?

1991 240 Sedan, manual transmission.

Thanks,
Keith