I live near Nashville, TN with many hills. My 2005 Blazer hesitates when climbing moderate rises or hills. This only happens when the RPMs are in the 1000 -1800 range. The RPM indicator “flutters” up and down and the engine revs up and down. It doesn’t appear to happen if I press the accelerator over 2000 RPM. It doesn’t happen when the cruise control is on. Heater use and AC use doesn’t seem to influence as it happens with heater on and off and AC on and off. It doesn’t happen in flat driving or steeper hills. Sometimes happens on down hills. Approx. 120,000 miles on the Blazer. Check engine light is NOT on. This started about four months ago very intermitantly. It is still intermitant but and has gotten more frequent in the past month.