1990 Chevy Corsica car shuts off

Shakes or Wobbles problem
1990 Chevy Corsica 4 cyl Automatic 89000 miles

My car will drive great for a couple of days. Then after a while the car will start jerking and shaking and cut off while your driving. I am able to start the car back up but once I put it in drive it cuts back off. It does the same if I put it in neutral as well. If it sits for a few days it runs great after a while it does the same. The mechanics that I take it to says that the there is nothing wrong when they look at it but there has to be does. We have tried changing spark plugs, gaskets, and see if the car is idled to low nothing seemed to work.