code p0320 on xg350
 

My xg350 with 208,000 miles started losing power when climbing hills and accelerating to get on highway. It finally threw code p0154 O2 sensor (B2 S1) which I replaced. The car is running much better but still losing power on hills. It just threw code p0320. I had my timing belt replaced last year and the mechanic said he accidently broke the crank position sensor. I wondering if he replaced it with an aftermarket part that has now gone bad. Does any one have any thoughts on this? Thanks!