Sooooooo, I had the frigging SES, TCS, SLIP lights which any 5th gen owner should now know is code P1320, which means, drum roll please, Bad Ignition Coil. I was also luckily enough not just to have code once, but twice and also to have a code P0300, which is multiple misfires. I was able to get the codes pulled for free from my Autozone and so I started my quest to fix my car.

Some background info: The original coils from Nissan are garbage and Nissan knows this, yet they have chosen to do nothing about it. They did however update the coils with "newer" ones with a gray dot, that were supposed to be awesome. Well I open my hood, take off the cover and guess what, all my coils have gray dots. So I guess that blows that idea up. I bought my car in 2003 with 80k in miles from Woodfield Nissan in Illinois. So at some point in time they had already been replaced.

Ok, back to my test, I donated to Maxima.org so I could search and spent a night reading about just bad coils. The general consensus is that you should replace all 6 when one goes bad. The rough best price was about $300 for all six. The only problem is that I have this in my life right now that causes me to be short on money.

So after reading, I found a few things that will help in changing just the bad coils as I have done. I can not take credit for this info as pretty much all of it has been tried before, I am just trying to make it as easy as possible for everyone else.

Step #1 - Autozone

You may be lucky enough to have an additional code stored in your cars computer. If you have code P1320 with any P0301, P0302, P0303, P0304, P0305 or P0306, that is a misfire on specific cylinder. You now know which one is bad just replace that one, see the pics below on how to remove the coil.

Step 2 - Unplug coil one at a time

Remove your cover by taking the four bolts off your cover, you will need a 4mm allen wrench.

This test will only work if your engine is running really bad idle. If your SES/TCS/SLIP only come on when your engine is under load this test will not work, skip to step 3. My engine was running really rough even at idle, so I started to unplug the coils on at a time. Just squeeze the clip and pull, it will come off.

The first one I tried cylinder #2, when unplugged, made no difference at all in how the engine ran. SO I instantly knew that one was bad. If your coil is good you engine will bog down and almost stall, as you are basically removing a running cylinder. Do this one at a time until you find the one, that when removed, your engine does not seem to run any rougher.

Step 3 - Testing the resistance

You will need a multimeter to do this. I have had mine for a while and it worked fine for this. Its nothing big, and you can pick mine up at Sears for only $19.99.

Remove all your coils. This is for 5th gen if you have a 5.5 here is a great write up for you to get to your rear coils 5.5 gen Write Up

The front three coils are right there held in by one 10mm bolt each. Unplug the clip, remove the bolt and pull. The coil will come right out.

The rears are little more difficult to get to, but the are doable. Some people remove this bracket but I didn't have to, I just slipped the cables out of the bracket and I got the coils out. If you are worried about dropping the screws an easy way to avoid this is to put two thin strips of electrical tape on your socket like this. It will all the bolt on the socket and it wont fall out. This is extremely useful for putting the bolts back on.

When you are done you will have 3 fronts and 3 rears. I labeled the pin #s I used to test them in the pics.

Your red Red probe is positive and Black one is negative. Set your meter to 20k on the ohm setting and start testing and make sure you write your results down.

My result were this. I already knew I had one bad coil, the one was making my engine run rough. The second one would only fail under a load, so that was the culprit I was looking for. The coil I knew was bad, is labeled bad, the two new coils I had bought were labeled as new.

I was looking for a reading from a coil that was different than the two good ones. If you look #4 had an infinite resistance reading (i) for +1,-2 and +1,-3, no other coil had that so I found the other bad coil! Also the weird thing was that the coil I knew was bad before had almost the exact same reading as the good ones other than the +2,-3 test (6.82) which is higher than any other coil. I replaced the one I knew was bad and #4 and have not had any problems since.
Where to buy: There many places to get the coils, but the Nissan dealership is waaaay too much. DaveB on the boards can hook you up for about $55 each roughly but you have to wait for shipping. What I did is if you have an O'Reilly's in you area they sell the coils for $51.99, but you have to have them shipped and wait the week again. O'Reilly Auto Front Part #UF348, Rear Part #UF363. Autozone carries the coils also Front Part #C1267 Rear Part #C1266 and I could pick them up tomorrow but they were $69.99. I told auto zone they O�Reilly�s has them $51.99 and they went ahead and price matched them. Perfect, 2 coils $51.99 each and I get them tomorrow.

Conclusions

I was able to replace only the bad coils and did not have to replace all and pay extra money. These test are not 100% proof positive but if followed, will give you a pretty good shot at replacing only the one you have to. If any body out has a for sure bad coil or has a brand new, gray dot coil and would like to put an ohm meter on it, please do. I would like to have your results and will make a spreadsheet to compare the results to see if we could figure out a 100% positive test. Just send them PM or email to me.

I hope this makes all us 5th gen owner�s life a little easier