Kelly osorno

So I had recently bought my 350z and it has been off since December but I had turn it on a couple of times each month. Recently I got it registered and it was running fine. It was throwing sensors like p0014 and p0024 which are the camshafts and I’m going to replace them. I went to the mechanic and was saying everything was fine. All he did was fix my air and told me what to get which was ABS pump module, ascd steering switch and rock and pinion that’s needed replacement. After I left I told him if he can fix my air cause it wasn’t throwing cold air. I then was driving down after like a week, my car started to delay on the road whenever I would hit a complete stop. One time it has turned off on me, the battery was on but the ignition turned off. I was reading that they changed the camshaft and the solenoid and still didn’t fix the problem until they change or replaced the flywheel ow what ever. Please. Need help