I cannot believe that not ONE person mentioned the POSSIBILITY of defective tires! I had this VERY problem with my 1999 Chrysler 300M for 10 1/2 months until I took control of the issue. The dealer(s) started with the usual BS- it's the crown in the road. Sorry, I've been driving new cars since I was 16 and the same roads also and NEVER had a car that felt like someone was under the hood pulling the wheel to go left right into the Jersey barrier! Then, they started with alignments again and again, then tire rotations again and again, then replaced rack and pinion steering components- can't recall what else they tried. FINALLY, one day after months of this BS, I picked up the phone and called Goodyear Corporate Headquarters and explained my dilemma. I asked if I could bring my car to one of their authorized dealers and have them drive the car. They made the arrangements and told me that if the tires were defective, they would replace them. The tire dealer called me at work and said that the tires were defective and they were all being replaced! The steel belted treads had separated.
Drove the same roads after that- NO pulling, drifting etc. STRAIGHT as an arrow! Some problems can be resolved with "life experience".