For a couple weeks now, when going up inclines in overdrive at low RPMS/high torque, the car bucks. It usually happens on slight inclines where it does not have to drop down a gear. So in overdrive, I will give it a little more gas, and it bucks hard. The first thing i tried was to replace the fuel filter, was not it. Then I read a thread about the MAF sensor. I have had issues where i had to replace that sensor before, so I tried unplugging the sensor to take it out of the loop. The other thread said if there were issues with the MAF sensor, unplugging it would clear up the issue and I would know it was the problem and to replace it. Well did it, drove it, still bucking. So now I havent any idea what it could be. It should not need a tune up as it was done about 20k miles ago. Any ideas?