Lately after about 30 mi. on highway or 30 min., I feel a surge and then RPMs' go up about a hundred and the gas mileage loses about 10 mpg. Could the tranny be downshifting? I've heard about a "shift control switch" on this forum, or is it time for that rebuild you are all talkin' about? 2001 SS 3800-THANX,Don

 

You're gonna need to tell us the year of the car and what engine/trans it has. I realize this forum is mostly 95+ montes, but there are a handful of older ones on these forums too.

Sounds like its either downshifting or unlocking the torque converter to me. I'd say its more likely the torque converter.

 

2001 ss 3800