2008 Equinox 1st gear issue
 

I have a 08 Equinox Sport with the slap shifter. In the manual mode 1st gear will rev to about 5500RPM then it seems like a governor takes over. it will spit & sputter until I shift it into 2nd gear. In the Automatic mode 1st gear will run all the way to the red line with no issues (just a little bit of torque steering)
The dealer says they cannot find anything wrong. Anyone have any ideas?
Thanks, Art