回复：初次DIY成功并请教下一次

这是请教的部分.怕WXC又把我的贴子搞没了,所以分开发.
前一阵我的2000 camry Check Engine 灯亮了, 查code是P0401和P0446.
拿到车行去看,结果是这样的,

Run diagnosis test and found trouble codes P0401 – egr flow insufficient
and P0446 – evap emission control system/vent control system.
Per test charts performed diagnostics on the egr system and found
the valve sticking and the switch n/g.
Continue with diagnostics test on the evap system and found
the evap canister n/g and the valve stuck n/g.

请教这样的诊断是不是可信? 怎么会四个东西一起坏呢?
如果真是这四个东西都要换, DIY的难度怎样?有什么需要注意的地方?
车行说这些东西寿命到了, 我觉得有点不太信, 因为车子才跑了7万5miles.
请各位高手踊跃发言. 多谢多谢.