之前的帖子

Background:  About a year ago I replaced the 4 spark plugs for my 2012 Subaru Legacy. It took me a while to unscrew the old spark plugs and took them out but when I tightened the new spark plugs pretty soon I felt it was already tight and I did not go any further because I did not want to overtighten them.  Several days alter my check engine light was on and the code was P0301 Misfire Dected in #1 Cylinder. I tried to tighten the spark plug again but it was still pretty tight so I just erased the code and the car was running fine for about a year.

recently the code P0301 came back again and if I erased it the check engine light will turn on again the next day. Now what can I do? I can bring the car to a dealership but just feel it is stupid if the problem is the spark plug is not tighten enough. Should I just try unscrewing the spark plug and tightening it again and see how it goes?  Or should i just let a mechanic to handle it?

原來的帖子快沉了，發一個新的繼續，

按著壇子裏有幾位建議先挪了一下1和3的coil, 之後一天CEL燈都沒亮，本來心中還期盼這樣問題就解決了，回到家一掃描p0301 pending. 這下應該可以確定不是coil的問題吧？下一步是不是交換spark plug再看看？如果是spark plug 1的問題直接換還是買個spark plug gap tool量一下先？這幾個spark plug都是大概一年前一起換的。