關於換火花塞，這裏說

"According to CarMD, replacing a spark plug on your own can cost less than $10. However, because faulty spark plugs can reduce your gas mileage or melt your car’s significantly more expensive catalytic converter, having them replaced by a certified mechanic may actually be worth the added expense. "

https://autos.yahoo.com/news/10-most-common-car-repairs.html

我這才自己換了，是在advanced auto parts 買的，bosch. 應該沒事兒？