Shakes or Wobbles problem
2000 BMW 528 6 cyl Two Wheel Drive Automatic 115000 miles

So I own a 2000 528i bmw... a couple of weeks ago the car started to shake, it feels like its in the engine. When i press the gas pedal it shakes more and less power. This happends about 3-5 times a week for about 10-15 min, when it starts to shake i turn the car off and it goes back to normal. I recently did a service hopeing it would solve the prob. but it still shakes. I got its sparkplugs, oil, filters, fixed an oil leak and it still shakes. What can the prob be...