2011 QX56: From rough idle to rough gas/acceleration

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chrisrach3

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I've had the good ol' 0430 code come on and cleared a handful of times over the past few months since I've owned the truck. Last time the oil was changed was February 2020. I bought it in October 2020, CEL (SES) light came on, was 0430, fed it Seafoam, went away. A month later it idled real rough, SES light was blinking, had it towed, mechanic asked when the last time the oil was changed, turns out it was almost a year ago. He changed the oil, cleaned some stuff, ran fine, I had to change it again 500 miles later, ran fine. Until it didn't, then another code came up (I forget which one). He changed the VVT solenoid, got it back, ran fine.

Until now. Started idling rough occasionally. I was on my way to get gas (gas was WAY low), SES light blinked a little, turned off, died on the way. I called the wife, she brought the lawn mower gas tank, filled the QX with that...ran the same, so turns out it's not the gas. Idled fine but revs went up and down when I hit the gas: New video by Chris Newkirk

Thoughts/ideas? (I had it towed to the mechanic, but curiosity kills...)
 
so what are the codes you are getting? are you getting P030? first thing to check is the obd.

we dont know what maintenance your "mechanic" did, so i woudl go back to him/her and get a line item on things they have done.

whats your mileage?

possible things that can cause the p030:

  • Faulty spark plug (s)
  • Faulty ignition coil (s)
  • Clogged or faulty fuel injector (s)
  • Intake air leak
  • Fuel injectors harness is open or shorted
  • Fuel Injectors circuit poor electrical connection
  • Ignition coils harness is open or shorted
  • Ignition coils circuit poor electrical connection
  • Insufficient cylinders compression
  • Incorrect fuel pressure
go to your "mechanic" with this info and ask them if they have done any of the things on this list.

have you had your compression checked?

did your car have the timing chain recall?

do you have the maintenance records from the previous owner(s)?
 
Thanks. I was on my way to a) get gas and b) check on codes when it sputtered out on me. I don't even know if the 0430 code came up on this one. Initial repair from the mechanic was from not having had the oil changed for 10 months. He said the oil was very dark and low. Said there wasn't engine damage but he had to change the oil and do some cleaning, I forget exactly what he cleaned. Maybe VVT solenoids? Sensors? Then there was another code, I forget which one, but it indicated that one of the VVT solenoids needed replaced, so he did. Then I got it back, no codes came up, but the car started sputtering, SES light would flash, RMPs would vascillate, no/low accelleration. That's when I just pulled over and had it towed.

It has 99,000 miles currently. I'm just hoping it's not the catalytic converters. The tow driver said he didn't think so. Haven't had compression checked, no recall on timing chain, I do have maintenance records, previous owner had it into Infiniti dealership every time for maintenance, no repairs though.

I've had a lot of good luck with my mechanic with other cars. He's been fantastic. It seems to me more of an Infiniti problem than a mechanic problem.
 
yeah there's an issue with the car for sure, but without knowing EXACTLY what your guy did to it, its a wild card of things to list that could be the issue. that's why i posted the possible issues so you can take that to him and have him run a diag on the engine.

with the car sputtering, it could have gone in limp mode, and if your guy fussed around on the VVEL's he could have messed up something. again, difficult to know over the internet.

it sure could be the cats and /or o2's. could be a leak at the cat, letting air in and burning out the 02's.

why wasnt the timing chain recall done? your car should be been on that list--or are you saying it was already taken care of prior to your purchase?

regardless, rather than chase your tail, get it back and have the car checked for codes. that's the first step.
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I believe I checked the vin with Nissan/Infiniti and it wasn't on the list for the timing chain. He's checking the codes now, we'll see. Praying it's not a cat.

He told me when I picked it up, I forgot what it was and didn't write it down, but just talked to him a couple days ago and he said it was some cam alignment code. When I picked it up a couple weeks ago, he said he just cleared the codes and erased the history, started it up, and it runs great. Still has since then. I changed the oil again right after I picked it up per his recommendation since he said it still looked a little dirty, dirtier than it should considering I just changed it in early January.

* So the oil was changed in February 2020 with 91K miles on it.
* I took it in this past January because of rough idle and blinking SES light and he said the oil looked really bad and really low, so he changed the oil and then I changed it again 500 miles later.
* Then I had to take it in again due to a VVT solenoid code and occasional rough idle. He replaced that, got it back, still rough idle, eventually limp mode, had it towed in again.
* 3/12/21: He checked the code, something about cam alignment, cleared/erased the codes, fired it up, ran great.
* As of today, 3/26/21, still runs great, but I'm just waiting for a rough idle or SES light again.

I've had the 0430 cat code come on occasionally but it would go away with Seafoam. Plus I don't smell anything and it performs great on the highway. The guy who sold me the car is pretty convinced I'm having all these problems because I'm using regular unleaded instead of premium, but I disagree and so does my mechanic. Plus I don't see how that would explain why the oil was so low and dirty back in January.

I'm hoping that it's just a matter of dirty oil taking some time to get washed through the system. If it's not that, I'll be taking it into Infiniti to have them solve this thing once and for all. (And hopefully for a reasonable price!) If it IS an oil related issue, hopefully the dealership will throw me a bone. The guy who sold me the car took it to the dealership for maintenance religiously, including July of last year, at which point they performed several other checks (including new battery) but didn't change the oil, even though the previous change was February 2020.

We'll see!
 
appreciate the backstory.

id side with the previous owner in that this engine *should* have high test aka premium petrol. these engines are direct injection engines. they are high performance and under high compression. thus it needs the highest octane petrol to keep it from detonating until the engine is ready for it.

sure there are knock sensors to retard the timing but again, with high compression along with the heat the engine produces, the fuel can still pre detonate under these conditions, causing reduced power and making the computer work overtime to prevent this. the VVEL system is working harder to keep things in line but they can only do so much.

also being that it is a DI engine, carbon will build up more easily so if using lower octane fuel, and if it pre detonates, it will deposit more carbon.

you have to do the ol' "italian tune up" to blow out the carbon on these guys .. ;) i would drive my 2012 like it was a rental. never had any issues with my car - ever. got it in 2011 and had it until 2020 when i sold it at 92K miles. lots of people just drive these as grocery haulers or mall crawlers, but that engine need to get hot hot hot and the revs needs to be high on occasion to blow the stuff out. :)

also, id change the oil out at 3 or 4k miles, because of the DI engine and carbon build up those engines get. i used nissans ester oil in the car and changed the oil at 3K for peace of mind.

well i hope its not our cats or o2 sensors but id still get the exhaust checked out to make sure there are no air leaks at the cats. hey can burn out the o2 sensors.
 
Thanks for the input. You don't think not having had an oil change for so long and having the bad oil go through the system would be the cause?
 
im not a mechanic so im can only offer an opinion.

did you use synthetic oil or dino/conventional oil? if the latter its possible it could have been worn out and, if you didn't drive the car much and the oil sat in the engine like this, it could have turned into sludge making it harder to be used as it should inside the engine.

again just my opinion. :)
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The seller changed it in February 2020, I assume with synthetic. He took it into the dealership again in July and they did a few checks, including replace the battery, but did not change the oil. About 3-4,000 miles later in January 2021 is when I had the issue where my mechanic noticed that the oil was very dark and dirty and low. I've since had the oil changed 3 times. Runs like a top now, but we'll see...I just wonder if the bad oil caused some sensor/computer issues. Back when I first had problems in January he did say one of the sensors was filthy as a result of the low/dirty oil so he had to clean that out. That's why I'm wondering (okay...hoping) that it's a matter of getting a few cycles of clean oil through to clean everything out.
 
yeah i hear what you are saying and yeah its possible. if the oil turns to sludge its useless for its intended purpose and can cause issues if left in the engine for long periods.
 
Well, 3,000 miles later and it still runs great, no lights, no sputtering...nothing. Drove it 3 hours away and back three times. I love this thing! This is what I thought I was getting!

I'll be getting the oil changed again within the week, then likely again after 4,500 miles. Running nothing but QuikTrip 87 grade basic unleaded. So strange.
 
what's strange about running 87? the computer will retard timing to prevent knock, but you get reduced power and , in my opinion, its not really good for the engine. its designed for high test because of the higher compression ratios, but again the computer is designed to adjust based on the octane so you should be fine for the most part.

now.. check this. :)

a few times i would put in 100 octane -- yes 100 octane!! -- and the car LOVEDDDDD 100 octane! i would barely tap on the accelerator and it would take off like a scalded cat! instant FUNK!!!!!

alas, i could not afford to do this every fill up -- these photos were taken in 2012 so todays prices it would be insane....

IMAG0254.webp

IMAG0253.webp
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chrisrach3 said:
The seller changed it in February 2020, I assume with synthetic. He took it into the dealership again in July and they did a few checks, including replace the battery, but did not change the oil. About 3-4,000 miles later in January 2021 is when I had the issue where my mechanic noticed that the oil was very dark and dirty and low. I've since had the oil changed 3 times. Runs like a top now, but we'll see...I just wonder if the bad oil caused some sensor/computer issues. Back when I first had problems in January he did say one of the sensors was filthy as a result of the low/dirty oil so he had to clean that out. That's why I'm wondering (okay...hoping) that it's a matter of getting a few cycles of clean oil through to clean everything out.
Click to expand...
Do you know what sensor?
 
Not strange about the gas necessarily...just the whole thing is strange.

And those pics are fantastic! Where in the world do you go to get racing fuel?!
 
I just found out, across the GW bridge over at Ft. Lee, NJ, about a 10-15 min drive w/o traffic is a Sunoco gas station that sells 260 GT. I'm gonna have to give it a try one of these days. :cool:
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chrisrach3 said:
Not strange about the gas necessarily...just the whole thing is strange.

And those pics are fantastic! Where in the world do you go to get racing fuel?!
Click to expand...
One of the Sunoco stations at the Daytona Speedway exit off I-95 in NE FL has racing fuel. When I was filling up there once, a guy was mixing a few gallons with premium, claimed he could totally tell a difference. I didn't want to try since it's basically an hour highway drive away from home.

Official Fuel of NASCAR | Sunoco Race Fuels

www.sunocoracefuels.com www.sunocoracefuels.com

Later,
pjdavep
 
its a difference and you can tell it. ive put 100 octane in my qx several times and its beyond night and day difference! the only issue is it was 10 dollars a gallon.. ;)
 
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