Hi, I'm new to the forum and am in desperate need of some help. I had a master ase certified technician replace the timing chains in my Buick. It has 153,000 miles on it. The chains had stretched but not jumped time. After the install the car would not run right. It just don't have any power. The code it had indicated a bad crankshaft Position Sensor. So he replaced it. It didn't make any change to how the car run. Any ideas or things that needs to be checked at this point? Any and all advice is greatly appreciated.