starting problems..
 

My dad got his Nissan for almost a decade already. I'm not sure how many miles did it run but he's using it everyday. Maybe the problem with the electric part of it started with the car's age. He has some difficulties in starting the vehicle. He don't want to send it to the mechanic because he say that he can do it alone. The problem was the Nissan starter, can we replace it by an aftremarket part? Another suspect was the spark plugs and Nissan spark plug wires. Do we need to have some hints before having it replaced? Where can we buy cheap brands? Really need your suggestions. Thanks.