Scratching/grinding Sound on acceleration

Don't really know cars too much, but browsing around I couldn't stumble onto anything.

About 3 weeks, in a different city, ago I had 98 rodeo go into get the intake manifold gasket? replaced since I had that rough idle thing going on. About a week or 2 ago, can't remember when exactly I've started to notice that at lower speeds when I accelerate I start to hear, what I can best describe as a scratching or grinding noise coming from my engine.

At first I thought that maybe something was dragging underneath, but I couldn't see anything?

Any ideas? Is it something I should have looked at?

I've got a 98 v6 rode with abour 45k miles.

thanks

Brake pads warning indicator?
S-Belt pulley bad
http://isuzufaq.ibctech.ca/#faq69

water pump going?

I would pop the hood and listen to see if you can pin point it.

sounds like brakes...probably needs claening or seized up or warped rotors?