Our vehicle started to buck right after we had bought the vehicle new. When we brought it to the dealership and told the salesman he said that service would check it. The answer came back that there was nothing wrong with the van. Then the van continued to buck, but it was a small amount. I had told service about this and they told me after checking that they could find nothing wrong.
Just recently we went to Virginia on a trip and the vehicle started to buck horribly. The check engine came on and stayed on. We had to call around to find a dealership that could get us in and look at the vehicle. When they checked the diagnostic computer they said that they found the P0300-random cylinder misfire detected, on P0305-Cylinder number 5. The misfire was detected and the trouble codes were stored in the PCM. They diagnosed the problem, which was "We cannot find anything wrong." Cleared the system and took it for a 6 mile drive. No more problem.
Within a couple of days home there it went again. Took it in and they said it was excess moisture on the mass airflow sensor. They wiped it off and cleared the PCM again. Now here we are not even a month later and the van is at it again. Check engine light and all. Except the noise is louder this time.
To add insult to injury, the lemon law in this state is for the dealers not the people. When the van acts up we lose power while driving and it bucks. We have five kids. Something needs to be done.