Stop at red light then all of a sudden check engine light P0350
 

03 Coupe- Car has about 80K miles, has been completely fine the last 5K miles i've owned it. 3 days ago was driving to lunch, stopped at a red light, felt a very slight judder/ hesitation, then everything felt normal again, but VDC and check engine light went on. Did the gas pedal tap dance to get the code when I was in my driveway and read it out to be P0350 Ignition Coil Primary/Secondary Circuit Malfunction.
Yesterday drove it to / from work, and check engine light did not turn on when i was driving. Today, had the same symptom on my way to work. at a stop light, while at idle, the car makes a slight judder and the CEL/VDC came back on.
Does this sound like a coil is going bad? The code makes it sound like it and does this car isolate down to an individual faulty ignition coil (my lexus does), or do i have to test resistance on all of them? Also, what other failures could cause this code to get thrown? should i replace the plugs as well?

I'd start by just taking the coil packs and spark plugs out and inspecting them. Also clean the ground system because poor grounds cause problems exactly like that. Top middle of the timing chain cover are two grounds, then on the passenger side of the timing cover that jumpers to under the coolant reservoir, finally the negative battery cable itself jumpers over to the chassis. Brush, electrical de-ox anti-oxidation grease (not dielectric grease, that actually BLOCKS electricity from flowing), reassemble and see if it goes away.

I used dielectric grease on all my grounds and everything is fine and the connections are protected from rust. But since you said that I googled it since I've heard differing opinions on the subject: https://www.w8ji.com/dielectric_grea...ive_grease.htm

Pulled quote "Both dielectric grease and "conductive" greases (anti-seize) are insulators. The primary difference between dielectric greases and "conductive" greases is that "conductive" greases and anti-seize greases include some amount of finely-powdered metal. The finely powdered metal is suspended by insulating grease, so it does not conduct. The suspended metal powder does lower the voltage breakdown of any arc paths through the grease. "

I really, really, really don't want to do my heat transfer pset right now.... lol

Trust me, you want de-ox. Anti-oxidation grease is designed to be applied directly to the mating surfaces of the conductor or lug to prevent corrosion from forming on contact surface, dielectric is slathered on TOP of a connection that has already been mated to prevent corrosion. In the field the only time we use dielectric is when you're dealing with open conductors in a high humidity or corrosive environment like the lugs on the overhead service to your house. Hit it with dielectric and wrap the hell out of it with tape. De-ox is usually used for the exposed part of aluminum wire or anytime you mate aluminum to copper and it's DEFINITELY conductive.

Today my apprentice went a little haywire de-oxing the 800A busduct we were installing and there was a big glob touching two phases together, when I meggered out the thing I was getting this wierd low reading of like 400mega ohms when everything should have been like 40,000-80,000 megaohms. Took me about an hour to realize what went wrong and that it was measuring through a great big glob of de-ox. Dielectric it would have megged out just fine without even a blip on the meter.

The reason you can get away with dielectric is because the compression of the lug to the mating surface actually digs the two metal pieces into one another and it's physically moving the dielectric out of the way but it's a pretty shitty connection electrically. We've mistakenly used dielectric on some of the big stuff at work once and those lugs get screaming hot from all the extra resistance and end up damaging the insulation for about the first 8 inches of wire.

I'll inspect the ground areas at lunch today. Thanks for the tips.

quick visual inspection indicates the grounds are pretty good. No corrosion or rust anywhere under the hood. I only removed the plastic engine cover to observe the grounds near the timing chain and coming from the battery. Not sure what the USDM ones are like, but on the JDM, all of the wires are completely insulated in an electrical tube. I've tried searching the web and doesn't seem like many people get this code at all. I have 6 spark plugs and an ignition coil on order- might as well swap out the plugs while i'm in there- its been 15 years and doubt its been done.

So I replaced all sparks w/ the OEM nissan NGK ones. The electrodes themselves look good on the old one . Threads had a little bit of oil on all of them, but not much to worry about. or it could be a bad valve cover gasket... I'm pretty sure they were replaced by the previous owner, as they were not the oem ngk's but the laser iridium ones.
Maybe he used the oil is a substitute for antiseize? I did the resistance check on all of the coils. they all showed resistance. One coil though showed 0 for about 5 seconds and then started showing a resistance. I swapped that one out with the new coil. otherwise, i couldn't see anything else that could cause my code. I did the gas pedal tap dance to clear the code, but only drove a mile with it so far. we'll see what happens tomorrow.

The oil is probably seeping into the spark plug well due to slightly failing gaskets in the valve cover, you should probably pull the coil packs out twice a year to keep an eye on it. The oil won't be any real concern until you start to actually accumulate some at the bottom of the spark plug.

yep, unfortunately that will be something the next owner will have to worry about. This is basically how all the plugs looked like.

https://cimg0.ibsrv.net/gimg/g35driv...b6d4d2b572.jpg

UPDATE: I tried to isolate which coil was bad, and replaced only one. but this problem kept coming back, so i finally just ordered 5 more coils to stop wasting time. This problem went away completely when i replaced them all. sucks that the P0350 code doesn't isolate down to a cylinder, but at least i know that they were coils.

The reality is at 80K miles on a 16 year old car replacing them as preventative maintenance is a good idea. Now that's one thing you can cross off that list. Glad you got the problem fixed.

On my '04 with 130k all of the coils are original except for one that I've had to replace. Those spark plugs looks pretty oily though so maybe that's got something to do with it, my valve covers aren't half as bad.