Auto trans dragging down to lower RPMs when letting off gas above 40 or so?

[trb]

My son's 2006 1.8 auto trans Vibe has started acting a bit strange. I first noticing it a couple of months ago. If I am driving at a steady speed in Drive, like 40-50 or so, and then let off the gas, it drags like I am putting on the brakes. The RPMs drop to about 1200 and then it feels like the transmission releases, the car stops slowing down as much, and the RPMs jump back up a bit. I don't recall it dragging down the car this much in the past, or having any other auto trans vehicle that drags it down as much. It kind of feels like I have it manually in a lower gear or something to use the engine braking. Before I have the dealer look at it during the next (free) oil change I thought I'd ask around here. I haven't had a chance to drive another used Vibe to see how different it is. We have the 5 yr GM Certified powertrain warranty that expires in October, so I will have it looked at before then.Thanks

[ehoff121]

Eliminating the obvious, is the overdrive button engaged? If not, an orange indicator light will be visible below the fuel gague "O/D OFF".The O/D button is on the left side of the gear selector lever, under the lever lock.

[jkm311]

My exact guess. Sounds ("feels") like O/D is not engaged.

[trb]

OD is engaged, the "OD Off" light comes on if the button is pushed. It is noticable, my wife even asked about it after driving the car last week. It has to be pretty obvious for her to notice! I may try and disconnect the battery and see if that does anything like resetting the computer/PCM. The only thing done to the car besides oil changes in the past year was a new battery about 5 or 6 months ago and they verified that it did have the newer PCM that the recall is about.

[jkm311]

I hope it's something simple like a dirty air filter, but it sounds more complicated. Does the accelerator feel "right?" When you let off on it, can you feel the proper amount of force following your foot back? It's drive-by-wire, so maybe there's a strange electrical/wiring issue. Maybe that PCM reset will do something after all. Stumped.

[cq358]

is it the grade logic it downshift when they sense you lift off the gas suddenly? It also serve a purpose of engine braking?