GMC Sierra 2500HD. Whistling noise around 1500 RRMs.
I've got a 2007 GMC Seirra 2500 HD. It started making a high pitched whistling noise at around 1500 RPMs. It only lasts for a couple of seconds. If I take my foot off the gas or I get above 2000 RPMs, the noise stops and it only happens once in a while (not every time I drive it.) If anyone has any ideas, I would appreciate it. Its driving me nuts!