The Engine in my Honda has been squeaking for a while now and I can't seem to figure out what it is.

All the accessory belts are in good working order. The air conditioning system is in good working order (I checked it because I thought an over charged system might tend to over work the compressor and put strain on the belt). Actually, the a/c system was overcharged and I had to correct this problem, but the squeaking still remains.

When I bought the car, it had 60,000 miles on it. At 90,000 miles, I had the dealer change the timing belt. I didn't realize until recently that there is a balance belt (Timing balance belt?). I see that this belt should be changed every 105,000 miles. I have 150,000 miles and have not changed it. Could this be the problem? Also the tech at the dealer thinks it could be the idler pulley (Just a hunch, he did not inspect it). It could be, but with research it seems that the balance belt may have something to do with the squeaking.

Note: The car doesn't sqeak constantly. It only squeaks when I accelerate the vehicle (usually around 2000-3000 rpm). If I am parked and I rev the engine to 3000-4000 rpm, I can hear the squeaking noise.

Any ideas? Thanks