I have a 1998 Chrysler Sebring JXI that stalls randomly while going down the highway. It will act as though I hit a small bump in the road and the RPMs will drop and the engine will be stumbling when I pull over. After about 20 tries, it will restart and go a bit further. It dies randomly no specific interval. I have replaced the following: Crank position sensor, distributor, plugs, wires, fuel pump & sending unit, TPS, Air charge sensor, O2 sensor, MAP sensor, and AIC. What's the problem? Thanks.