Hello all,

I have 2000 4runner SR5 4x4 auto with just over 200,000 miles. Recently I have had an interesting bump it seems to be related to when the rig is at speed and wants to shift down. It almost feels like a misfire but the intensity it shakes just one bump or a few in a row i would think would cause the ECU to throw a code. If the rig starts to have this issue and a give it a lot of gas it shifts down no problem and is ok. I feel like it could be overdrive related but also had the same issue when climbing a very steep long driveway it did the same thing I manually shifted down to L and it was fine. I am really lost on this one. Transmission fluid is perfect level and color and scent. Only code I have right now is P0420 but this rig has had that code off and on fixed with upstream O2 first time and still need to put in downstream to see if that takes care of it. Would love some direction on this. Thanks Guys.