Misfire in Altima 2.5

[Tom NJ]

This is a 2019 Nissan Altima with the 4 cylinder 2.5 liter PR25DD engine. Ran fine last night, parked it overnight in my garage, and next day it ran rough when started. It is throwing a P0302 code indicating a misfire in the #2 cylinder and the Check Engine light is blinking.

I swapped the ignition coil with the one from the #1 cylinder, and again with the one from the #3 cylinder, and it continues to throw a P0302 after running for a few minutes. I think that eliminates the coil as the culprit (?). I can't remove the spark plug (Denso DXE22H11C Iridium tipped) because it requires a special thin socket that I don't have. The service interval for the spark plugs is 105,000 miles and the engine only has 44,500 miles on it, always with Top Tier gas, so I am assuming the plug is likely good. That leaves fuel (injector?) as the more likely culprit.

Is there a way for me to easily confirm this (I am not a mechanic)?

If I can confirm it is a fuel issue I can drive it to the shop without worrying about unburned fuel damaging the catalytic converter. Speaking of which, if it is the plug or some other electrical issue, and some unburned fuel does pass through to the catalytic converter, do you think I can drive the 25 miles to the shop without any serious damage? The engine runs okay, just a bit rough, especially at low speed.

Thanks!

 

[LongTime_Lurker]

A blinking check engine light indicates a catalyst-damaging misfire and it would be best to not drive it until the issue is resolved. Have the vehicle towed to the nearest service center.

 

[JeffKeryk]

You need a 14mm socket for those plugs; not that special nowadays.
As you say, 45K is like half-life for them. And really low miles for a coil...

 

[OVERKILL]

I'd recommend getting the right socket and pulling that plug first "jut in case".

 

[michaelluscher]

Losing coolant or oil?

 

[D60]

Do you have rodents or any signs of droppings, etc?

For such a problem to manifest literally overnight seems odd, but not necessarily impossible.

 

[D60]

Also I'd just check and clean your MAF. I had a fried bug cause a ton of problems on a '14 Rogue, and it would sometimes trigger a P0300 or P0302.

To be clear, the MAF thing is a long shot in your case, but I suggest it because it's 1) quick and 2) free

 

[mk378]

Spark plugs can crack internally and suddenly fail to fire. That needs to be near the top of the list of things to check next.

 

[GSCJR]

Losing coolant?

This @Tom NJ. I'll bet your coolant reservoir needs topping up. Any white smoke? Does it eventually smooth out at all?

 

[michaelluscher]

This @Tom NJ. I'll bet your coolant reservoir is needs topping up.

I'd still pull the plug for a visual inspection
And I don't know if the 2.5 Nissan is afflicted with coolant intrusion

But didn't a member on here somewhere also have an Altima that was misfiring/losing coolant?
Nissan got involved and it was an EGR cooler?

I can't remember

 

[Craig in Canada]

You could pull the connector on the #2 injector and see how things change. e.g. obviously it won't be running right, but does the "catalyst damaging" flashing check engine light stop? It could be misfiring, clogged, or stuck open (which means the cylinder is being flooded with fuel, working it's way into the oil etc...) DI engines can even hydrolock from a stuck injector - not fun. What's your oil smell like? Has the oil level risen since this started?

What a perfect thing to have to deal with on Dec 23

 

[KrisZ]

I would tow it. A blinking check engine light means severe misfire and will damage the cat converter. Not worth the risk of driving to the mechanic.
Maybe if you can unplug the spark plug and the fuel injector. But in current condition I would not drive it.

 

[FowVay]

I agree with much that's already been said. Do you have any sort of extended crank on cold starts? If the injector is leaking down then you could possibly borrow a fuel pressure gauge from the local parts store and take some measurements during running and after sitting for a night. If the pressure bled down to near zero then you can assume the injector is leaking.

Check for coolant loss at the reservoir. It'd be much better if you could do a plug comparison across all cylinders to determine if you have coolant ingression in the #2 cylinder. And ultimately, removing the spark plug and using a borescope tool to peek inside would be primo.

Please let us know what you find out.

 

[Trav]

Always start with the basics, remove the plug, I would try a new one anyway. A socket From AZ cost $7.50

https://www.autozone.com/ratchets-sockets-and-wrenches/socket/p/duralast-3-8in-drive-14mm-deep-6-point-socket/482578_0_0?spps.s=5018&cmpid=LIA:US:EN:AD:NL:1000000:TLS:19489353547&&CATARGETID=120054150001289977&CADevice=c&gad_source=1&gclid=EAIaIQobChMIr-inp8KmgwMVy1FHAR2KZgxxEAQYBCABEgLu8_D_BwE&gclsrc=aw.ds

 

[Tom NJ]

Thanks y'all for your helpful advice. I am not losing oil or coolant, and the oil is full and clear (not milky). We do get mice from time to time in our garage. I did not see any signs of wire damage, but of course that can be hard to find. No white smoke or raw gasoline smell from the exhaust.

I'll clean the MAF sensor on Tuesday when I can buy some CRC MAF cleaner. I'll also see if the local NAPA store has the special thin walled 14mm spark plug socket (my 14mm sockets do not fit around the plug the way it is configured, and I read that a thin walled socket is necessary). If I can find one quickly I'll try the plug swap or replacement.

So far I have not been able to find the injector connectors but will keep looking.

If all else fails I'll have it towed to the shop. Sounds like it could be damaging to drive it the 25 miles.

 

[The Critic]

A 2019 may still be covered by the 5/60K powertrain warranty, no?

 

[JeffKeryk]

I think this is the 14mm plug socket I bought. If I had to do it over, I might go for a magnetic socket. Good luck.

 

[cronk]

My first though with this sudden issue after sitting was rodent damage to the wiring.
Pretty common in the car repair world these days. Damaged wiring to the coil packs and injectors is common, but sometimes even main wiring harnesses and fuse and relay box areas can be targets.
Of course if the wiring checks out ok, I'd probably start looking at a possible spark plug or injector issue.

 

[Nukeman7]

I think this is the 14mm plug socket I bought. If I had to do it over, I might go for a magnetic socket. Good luck.

This spark plug socket is ideal for your situation if the 12" extension is not too long for your application:

14mm Spark Plug Magnetic Socket with Swivel Extension

 

[Tom NJ]

My 14mm sockets with an extension reach the plugs, but will not connect because of the configuration around the plug. It requires a thin walled 14mm socket.

When I bought this car in 2019, the deal was that if I had all scheduled maintenance done at the dealer (which I have), oil and filter changes every 5,000 miles were free for life, and the engine was guaranteed for life as well. We'll see if they honor that, if it turns out the problem is with the engine (as opposed to wires).