I have a 2006 6-cylinder Trailblazer, 4WD, 125,000 miles.
I have a 30 mile daily commute, on the expressway running about 70-75 MPH.
Lately, every day at the same point in the commute, the RPMs suddenly shoot from around 2400 to over 3,000. I can hear/feel a difference. I have to back down...