06 M35X misfire/running rich [SOLVED]

[hellabuck]

Hello,

Recently got a 2006 Infiniti M35X with some engine problems for $1800, it has 180 000 Miles, and is running lean (can smell gas at idle) and rough

It was a company vehicle previously so its had its oil changes and service records arent bad, not smoking. Hoping I can get it running right, everything else is in good shape. If not, I will have extra parts for my fathers 06 M35X and part out other stuff, but I would really like to drive it for a while before that!

SES Light is on/flashing and the codes are:

P1148 - closed loop control function bank 1
P1168 - closed loop control function bank 2

P0300 - misfire code

Before I swapped the bad battery the gas level was reading wrong (full tank when it only had half), had a fuel level sensor code also, P0462, the fuel level now reads correctly since changing the battery so im hoping the code will be gone as a result. (havent rescanned it yet)

Have so far just replaced the battery and air filter - it had no air filter in it when I got it (!!!) which is quite alarming - I ordered new OE spark plugs and also a gasket to fix an exhaust leak after the passenger side cat, will update when those are installed.

Looking for recommendations at what else to look at, thank you

[EdBwoy]

Hello and welcome to the forum. Might you have seen this thread?
p1148-and-p1168-closed-loop-errors-afte ... 14247.html

There might be some answers for your closed loop control issues. Check the fuse, then the sensors might be due for replacement.

No idea why they would run it without a filter, they're cheap enough to not risk it.
When you get a chance, also clean the MAF sensor (when cold), as it might have been compromised by dirty air. If you haven't gotten any codes for it, don't stress over it.

You're on the right track with the spark plugs. I think the PCV valves are not a bad deal either.
Keep the valve cover gaskets, air intake gasket and injector O-rings at the back of your mind. I don't change gaskets for the sake of it, but keep an eye on those.
Get the engine running right and hopefully you don't have to smell any more fuel.
Step by step will do it.

[hellabuck]

Hello and welcome to the forum. Might you have seen this thread?
p1148-and-p1168-closed-loop-errors-afte ... 14247.html

There might be some answers for your closed loop control issues. Check the fuse, then the sensors might be due for replacement.

No idea why they would run it without a filter, they're cheap enough to not risk it.
When you get a chance, also clean the MAF sensor (when cold), as it might have been compromised by dirty air. If you haven't gotten any codes for it, don't stress over it.

You're on the right track with the spark plugs. I think the PCV valves are not a bad deal either.
Keep the valve cover gaskets, air intake gasket and injector O-rings at the back of your mind. I don't change gaskets for the sake of it, but keep an eye on those.
Get the engine running right and hopefully you don't have to smell any more fuel.
Step by step will do it.

That fuse was indeed broken, I changed it, still runs rough, going to check the coil packs tomorrow while I wait for the spark plugs. MAF appears very clean so I havent tried cleaning it.

Thanks!!!

the title should have said running rich by the way rather than lean...

[EdBwoy]

I'll correct the title.

Glad you're sorting the issues out. Any new codes? Try to reset the ECU by disconnecting the battery overnight.
I forgot to mention. Checking the throttle body for cleanliness and the intake tube to ensure there are no leaks after the MAF sensor.

[hellabuck]

update:

Changed the spark plugs, found 2 coils, for cyl 6 and 5 that were loose which explains the misfiring. I also fixed the exhaust leak after the cat.

It is running much better now, no more misfiring or shaking, but it is idling higher than our other m35 and im getting some white smoke from the exhaust now which is my concern now.

The throttle body was super clean, surprisingly a lot cleaner than our other M35 with half the mileage

The fuel level sensor has stopped working again and is showing a full tank when its actually pretty much empty, code P0462, could

Going to safety it in the next day or so and drive it to see if that helps, it has barely been driven for the past year.

Haven't checked the codes yet but will have a buddy come over with his scanner soon to find out.

[Costee]

...it is idling higher than our other m35 and im getting some white smoke from the exhaust now which is my concern now.

The throttle body was super clean, surprisingly a lot cleaner than our other M35 with half the mileage
Haven't checked the codes yet but will have a buddy come over with his scanner soon to find out.

Super clean? Maybe there's been a previous attempt to clean the throttle body, and which would explain the high idle. Yes, run a scan. A P0507 might be lurking around.

[EdBwoy]

... found 2 coils, for cyl 6 and 5 that were loose which explains the misfiring...

Out of curiosity, did you find the electrical plugs loosely connected or was it that the bolts holding the coilpacks to the valve cover weren't pressing them down enough?

Then, yeah, as Costee suggests you might have some idle relearning to do following that throttle body.

[hellabuck]

... found 2 coils, for cyl 6 and 5 that were loose which explains the misfiring...

Out of curiosity, did you find the electrical plugs loosely connected or was it that the bolts holding the coilpacks to the valve cover weren't pressing them down enough?

Then, yeah, as Costee suggests you might have some idle relearning to do following that throttle body.

The cyl. 6 bolt was sheared, I had to use an ez out to remove it, the cyl. 5 bolt was just loose. Electrical Connections were all fine.

[hellabuck]

Well it runs pretty well now, but theres some pretty major rust on the rear part of rockers (inner and outer rockers, basically all the thin metal inside the rockers around the jacking point in front of the rear wheels), its bad enough that I'll have to reinforce those rear jacking points also somehow as well as patch the rocker hole.

Luckily the rust is only really in that area on each side.. I would definitely recommend keeping a close eye on those areas, i think it would be fine if that area had been oiled and the dirt cleared out every so often by previous owners.

Mechanic said he'd certify it if I just bogged it but im going to try to do a decent job... bringing it somewhere to sandblast all the things tommorrrow

If anyone knows of a M being scrapped I might be interested in buying the whole rear rocker section if they'd be willing to cut it out

[EdBwoy]

Glad you got it running well.
When you mention bodywork, I exit through the emergency door. You've got your work cut out for you. Good luck.

Also, if you don't mind, update your location in your user profile. It helps in times like these as people close to you will keep an eye out.

[hellabuck]

Yeah not fun stuff but at least I wont feel so bad driving it in winter.. these cars are fantastic winter cars.

Got a quote for around $500 today which Is quite reasonable, to fix rear rockers and a couple wheel well holes.


Anyone elses M rotting out yet? lol