Mechanics

ODD DOWNSHIFTING ISSUE

Pontiac Grand Prix

I have a 2004 Pontiac Grand Prix GTP, 51K miles, with a 3.8 Supercharged V6. Recently I installed an aftermarket amp and speaker system, and since then I've noticed something odd with the way my car downshifts. What happens, is that when I'm in 3rd or 4th gear, and as my RPMs come down at about 1500RPM the car will downshift, and will upshift if I throttle back up. I think that I may have recycled one of the computers by unplugging the negative terminal on my battery when installing the power cable for the amplifier.
Avatar
Jmg53
August 23, 2007.



Check out the related content below while we wait for the question to be answered by a professional mechanic.