Gen 3 Shifting Problem

[dadismanc3110]

Hello everyone. My 3rd Gen GXE was shifting beautifully the first 3 months. Now it still shifts, however, when im on the interstate at speeds of 50+ im in the 4000 to 5000rpm range. It feels like its not ingaging but then I let off the accelerator and repress it quickly and the rpms drop and become stable around 2500rpm. It also looses powert at low speeds while going up a hil in od. Ill switch the od off and the rpms shoot higher Ive tried switching the sport comfort switch on the center console and i dont notice a real difference. Any advice is greatly appreciated.

[MinisterofDOOM]

From your description, it sounds like the car is shifting, just not when it's supposed to or when you need it to under increased throttle. I would check out the Throttle Position Sensor (TPS). If it's not calibrated correctly, it can cause problems like yours. OD Off simply disables fourth gear, forcing a downshift into third, which is what helps with power and increases RPM. That should happen BEFORE the car starts losing power, so the fact that you're having to do that is another sign that the car's not downshifting correctly when it should.

As to the power/comfort switch, that simply changes when (RPM-wise) the car shifts when NOT under load. In power mode it will wait longer to shift, whereas in comfort mode, it'll shift at lower RPM for smoother shifts (and better fuel economy). Left in the middle, it does its own thing, but behaves closer to Comfort mode.

Here's a thread with instructions for calibrating the TPS on a KA24 four-cylinder. The procedure is basically the same for our engines as well, so you should be able to use this for your Max.