[timo1980]

I just did two data logs and on both there's 3 degree timing correction on cylinder 1, and 0 correction in all of the other cylinders in the high rpms. My spark plugs were replaced about 2k miles ago by the dealer. Ever since the plugs were replaced my car idles near perfectly, with the exception that every 15-20 seconds it acts like it experiences a very tiny missfire, and the rpms barely move down from 650 for a split second, but really hard to notice if you look at the rpm gauge, and very obvious when you are inside the car. It idles this way pretty consistently. I think that either the dealer put a bad spark plug, or the coil pack needs to be replaced, is that correct? There are no codes at all when scanning with the accessport. I'm running the acn91 drive map and I'm mixing 2.5 gallons of e85, so I'm pretty sure that it isn't fuel quality related. The car has 45k miles. The attached graphs have rpms and timing correction, and the first graph has the actual cylinder 1 timing too. I guess my question is, if this 100% looks like bad coil packs, or it could be something else? I just ordered a new coilpack, but wanted to double check could be anything else? Also, is there any chance that I can convince the dealer to fix it without any codes?

[enrita]

Could be injectors as well or carbon build up but if its not missfiring dont worry about it. Correction is fine.