My daughter's 2005 Envoy (145k miles) had the check engine light come on a couple of days ago (very cold out......around 5 degrees). It is idling kind of rough and the check engine starts flashing when I get it above 30 MPH. I took it to the auto part store and they ran a diagnostic and it is showing code P0306 (Cylinder 6 Misfire Detected). Is my first step to replace the spark plugs (it's been over 50k since they have been replaced)? Thanks!
Code P0306 (Cylinder 6 Misfire Detected)
- Thread starter pmsmith2032
- Start date
Sparky
Member
- Dec 4, 2011
- 12,927
Firstly I'd pull the coil and make sure there isn't any watery crap in the well. Then swap the coil pack to another location (say switch coils 5 and 6), clear codes, and see if the misfire follows the coil to the new cylinder or not.
HARDTRAILZ
Moderator
- Nov 18, 2011
- 49,665
Thanks! I swapped the ignition coil as suggested and now it is showing a misfire for cylinder 2 (the cylinder I swapped with). What is a good brand to buy for a replacement? Delphi, Denso, ACDelco? I believe the factory ones said "Delphi".
Mooseman
Moderator
I think any of those would work. Delphi is original and ACDelco is just Delphi in the box according to pics on RA. Don't know about Denso but looks like a Delphi. Had bad luck with a Standard Motor Products not lasting long. I'd say get Delphi as it seems to be the cheapest of the three.
Eric04
Member
Standard seems to be another of those brands that used to be good. When a coil puked on me this summer I went with the best deal I could find on an AC Delco. No issues. I did buy an internet cheapie from a seller that I've had good luck with but just to have as a spare.