94 XLT chirping problem

I have recently purchased a 94 XLT and I have discovered a chirping noise. The frequency of this chirping increases as the RPM increase. It won't chirp until about 30 mph is reached (not in idle). I don't have a lot of funds ($) right now so I was kind of hoping to solve this problem myself. I assume that it isn't a belt or it would chirp at idle. My next thought would be something in the intake system is allowing air to escape. It doesn't chirp all the time, but once it starts it will continue for a considerable amount of time. I am new to Fords and SUVs so if anyone could point me in the right direction it would help immensely. Thanks.