My '99 Infiniti I30 had a mis-fire and turned on the check engine light....

[Charles R]

...Took it to the dealer and ....? The dealer said they have to replace all 6 of the ignition coils at a cost of $1000. Why? Because the code doesn't tell them which cylinder mis-fired. How can I find out which cylinder mis-fired? I'd like to replace the bad coil, not all 6 of them!

 

[supercharged]

...Took it to the dealer and ....? The dealer said they have to replace all 6 of the ignition coils at a cost of $1000. Why? Because the code doesn't tell them which cylinder mis-fired. How can I find out which cylinder mis-fired? I'd like to replace the bad coil, not all 6 of them!

had the same problem about 1 month ago...and was able to fix it myself...
I went to Auto Zone and rented a code reader (basically you pay the full price on it ~$160, and then return it for a full refund). It should tell you which cylinder misfired (will give you 2 codes)... But be sure to do this check after driving your car with a "check engine" light one for about 2 weeks...
if not, ask them for a different code reader (sometimes they have two different kinds)...
That's what I did...Then I bought an ignition coil for ~$80 from Autozone (they had it in stock, and cheaper then Kragen, or Napa), and replaced it myself... I saved my old one, just in case...

Hope this helps...Good luck...