Hello Scotty! I just found your page today and wow! My new favorite auto page. Great videos. So I watched your misfire video earlier. I am working on my girlfriends car. It has a terrible misfire. Loss of engine power when driving, poor and rough idle. Its a 2010 Hyundai accent with about 66k miles. I first thought spark plugs, which we are checking tomorrow. She took it to a mechanic who scanned and said misfire cylinder 3 and said it was probably the fuel injector... So... She bought that and had me install it. Got that all done and replaced injector 3 (I guess he voltage tested it). Turned it on same result. Flashing CEL and violent shake that levels out. So we turned the car back off. I am checking the spark plugs visibly tomorrow and will throw some new iridium NGK ones in if need be. I also plan on swapping coilpack three to a different plug and using my bluetooth dongle to see if the error code jumps to a different cylinder. Outside of those two things anything else you can think of? I have seen some horror stories of people with these Hyundai's getting CEL codes and literally replacing all coils, plugs, injectors and still having issues. Its a real nightmare and it happened 1 day after she posted it for sale.... otherwise its been running good up until this. She blames Mercury being in retrograde. I'm looking for a more scientific answer (and a solution hopefully).
Sorry for the rant but that is the problem. Let me know what you think the culprit may be. I also read its possible the intake gasket could be it. I'm pretty new to the whole DIY mechanic game but with the help of youtube I replaced the entire rear end suspension (coils, shocks, trailing arms, control arms, sway bar, links), and all the engine mounts, all serpentine belts and accessories and the front control arms and tie rods on a salvage Mazda 3 I bought last fall... As well as some body work (body fill, de-rusting and painting). It was a money pit, but the parts where cheap as it was a 2004 and I learned SO MUCH!!! Anyways I hope you can send some advice on chasing the ghost of this accent misfire issue so my GF can get this thing sold without spending an arm and a leg. Thanks Scotty! Keep the videos coming! I have about a million old ones to catch up on in the mean time.