missfire

[Tuner923]

i had a miss and backfire issue, i started using gas from sunoco 93 octane only fixed my miss and back fire problem. if i go to other gas stations when im in a pinch.. backfire and misfires return.

to rule out the coils as the source of the misfire take coil 2 install at cyl 1 take coil 3 install at cyl 4. now if the misfire follows to a misfire at cyl 1 and 4 instead of 2-3 its the coils.

if the misfire remains at 2-3 someone should look at the trigger pattern on a oscilloscope. from there you can rule out if the coil is burning out or if the pcm is glitched.

also did you ensure the plugs were gaped? i NEVER trust the gap from the manufacturer, they bounce around in shipping and can lose the spec. also small cracks in the ceramic can cause misfires.

---------- Post added at 01:21 PM ---------- Previous post was at 01:11 PM ----------

also fyi i had a complete coil failure at less than 25,000 miles.

[tooo_much_fun]

I moved the coils around and put new plugs in. The misfire seems to be gone idle. i will drive it a bit and let you know how it all works out. Thanks for all the good info.
Mike