I have a 1995 Chrysler Lebaron it has only 70,000 miles on it .. about a month ago i noticed the car start to shake after running some errands around town..it then smelled like gas and white smoke came out of the tail pipe. took it to the mechanic who said it was the head gasket and replaced that with a new water pump, and timing kit..when i got it back it was fine while i ran a few stop and go errands ( about 1 hours worth ). after i got it to one of the errands and had it parked for just 1 hour and i started it up.. it shook , smelled of gas again and the white smoke.. sent it back to mechanic.. they were puzzled , but did find a small crack in some cylinder, and replaced that. i got it back home and after driving and stopping and going for about 1 1/2 hours, i brought it home. parked it and had a hunch to start it after it sat for just 1 hour.. sure enough it happened all over again..what is wrong with this car??