问：在道奇2010 Nitro 3.7上

Nitro有时会失踪，然后跑得很好……就像一个坚实的错过...光线亮了，说第4缸丢失了，并且一侧是线圈的。车辆仍然运行正常...我需要做什么.....将要更换所有哈巴狗和插头电线，但被告知有3条插头电线和3条线圈线...从未听说过。。。。and now the egr valve sensor light popped on...trying to figure it out to buy the parts and have them installed by a certified Dodge mechanic after he quoted me almost $400 for just the 3 coil wires and 3 plugs on the A bank...why so much?....and how much should it run to just replace all the plugs and wires? and how about the EGR valve? How much to buy one and replace it?

我的汽车有180000英里。
我的汽车有自动变速箱。