As i took off from a stop light, the van jerked so hard , it felt as if it was hit from behind. the next light within 5 miles, the same thing from a stop. a few days later it was much worse and the service stability control system code came up. after having it checked( immedialely), there was no code found in the vans computer. it didn't show that it ever came up. this could be fatal, especially at high speeds. when the code comes up and a mechanic can't get a reading to address the problem. doesn't that indicate a problem ?