P0301 Toyota - Yaris 2008 Cylinder One Misfire

Question

Check engine light came on and car started running rough (hesitation, rumbling, decreasing in speed & having to shift down to 3rd & 2nd gear to pick speed back up)....it is a 5-speed 2008 Toyota Yaris....thus, went to O'Reilly's to put on diagnostic machine and was told it is a Cylinder One Misfire. He advised me to start with changing the spark plugs, in which I did immediately. However, it's still running the same. But I noticed that one of my wires was nearly split all the way. (I'm thinking that THAT is causing the problem). However, went to Advance Auto and they informed me that they don't have that particular part and O'Reilly's stated they don't either (I don't understand why the auto parts store don't have it) and I will probably have to go to the Toyota dealership to get it which is expensive (my last resort). Nevertheless, I went to a couple of mechanic shops and told them exactly what I stated here and pretty much I think some are trying to take advantage of me bcuz if being a female (u know how mechanics do), even trying to charge me $100 to run a diagnostic test ONLY to find out the exact problem of the Cylinder One Misfire. However, I have a picture of the frayed wire... I'm still thinking this is the problem...do I need to replace the wire or the whole coil pack??

Answer 1

Replace the coil pack with the sparkplug wires, unless you can test the ignition coil with a ignition coil wire using a ignition analyzer, This is the reason for the diagnostic test. Most misfire condition start at the ignition coil,