So I pulled everything from alternater to starter and two batterys and replaced tires down to doors on my sweet looking money hog car.. NOw lights come on and off batery check engine and then loses power Could it be my stereo electrical in this car

Wow, I am sorry to here that,sounds like it needs a good guy to go over the system a little , but try this first ,,connect a light tester to the frame work of the car then put tester on negative side of battery , if light comes on you have short in a ground wire some place ,,always buy a repair manuel for your cars even if you cant fix it your self it will help you understand your car and any repairs it might need depending on problem it has, then you can do proper repair 1st time and not waist money that is needed for household and rainy days ,,read that book some it will help alot,the more they put into a car the more can go wrong ,,,I feel for ya all ,thats why im switching to a 73 VW thing its air cooled and simple,I got sick of some cars or trucks haveing rust issues in water systems and pumps going out ,gps music and going down the road thats all I need ,lol ,,catch ya later