My truck is making an odd chirping noise at really random times but seems to be getting worse. To me it sounds like a belt chirp but only happens with the ac on and under load. Revving in neutral doesn't seem to cause the noise. Noise gets louder when it happens under higher throttle positions and it does seem to cause a change in the way the engine sounds and feels at that exact moment. Its hard to explain and its not really a miss but you can feel the engine react to whatever is causing the chirp.

I don't think its the belt because it doesn't happen constantly like a bad belt would.

 

Maybe look at the belt and tensioner. I have replaced lots of those tensioners because they are weak or the pulleys are noisy.

 

I have heard that about the tensioners being weak. Is there an aftermarket upgrade available? I know Katech makes a tensioner for the standard belt. What about for the ac belt?