Hi,

I own a 2000 Maxima SE and I am getting a P303 code for the cylinder number 3 missfire. I have changed all six spark plugs with platinum ones a few weeks ago. My question is this, my spark plugs were in bad shape when I replaced them, and I am thinking its the Ignition coils, would I be correct?

Thanks,

Maximusdriver

 

The P030x group of codes is a bad coil at least 80% of the time. Swap the cylinder 3 coil with one of the other cylinders and see if the problem follows the coil.

 

Thanks, I will try that.

 

I battled this problem for a few months but have solved my problem. I replaced spark plugs and OEM coils. Car ran great but check engine light would still come on from time to time with P300 OR P302. Decide to try replacing O2 sensor in the exhaust manifold and bingo no more check engine light. Been 6 months now and no CEL. Car idles great and runs nice and smooth. Worth a shot.

 

Thanks for the Info, I am gonna start with the ignition coils first, and see where that gets me. And if that doesn't work, I will do the o2 sensor. Thanks again.

 

I assume you only replaced the front sensors, right?