I noticed the other day that the idle/RPM's on my 06' M35X have changed from the normal 650 RPM's to 1000 RPM's. There are no performance changes but obviously and increase is not good when put in gear or when stopped at a light. M has 99,000 on the clock. I've never had the throttle body cleaned as I've never had a problem with the idle. Appreciate your comments.

You can try the idle re-learn procedure (if you search the forum you should be able to find it) to see if that resets it for you. But it may be also worth cleaning the throttle body (just be careful not to mess with the butterfly valve too much...be gentle. It's sensitive.

Ilya, Thanks for the your comments. Heading north for the holidays so the M will be parked at the airport for a week. Ill mess with it when I get back. There's a good tech shop I trust locally so I guess I'll have them clean the throttle body when I get back. Probably have them change out the NGK Platinums while it in the shop given the milage. Would a dirty air filter cause this idling issue?

The is an update to my previous post regarding increased ideal speed on 06'M35x. I realized AFTER previous post that the M also thru a ODB II code PO171 system too lean (Bank 1). I drove the M 2 hours ago stopping at the store. I came out of the store, started the car and the code was gone. Never saw that before. The car has thrown codes before but never removed the codes. There are no performance issues with the car. No stumbling, no hesitation, no nothing. Sounds like the engine is getting to much air relative to fuel. Could a bad PVC valve create this condition? Anyone else ever experience this condition?? Thanks.

Would a dirty air filter cause this idling issue?

Could a bad PVC valve create this condition?

Yes to both...as well as a leak in your intake tubing etc. I'd check the spark plugs, MAF as well, why not.
I was also curious if your fan module is functioning OK - your coolant fans don't constantly run, do they?

EdBwoy I changed the fan module at 87,000 on 2/3/2018. I installed the fan module (Beck/Arnley 203-0276) based on a recommended post. Bought it on Amazon as posted. To your point, I've noticed that the fan does run more than when installed. Doesn't run at start up but is running much more during driving time. Every time the car is at stop to shut off, the fan is running. I don't think this is right. Air filter had 8000 on it changed it tonight.M has 99000 on the clock. Its going in for NGK Plat plug replacement and Ill have the PVC valve replaced as well. Should I change out the module with one from Infiniti parts or can I go to a local parts shop. I believe the fan is running more than it should and maybe to fan module I bought failed. This I've done before and posted procedure. Appreciate ya.

EdBwoy Curious why you asked about the Cooling fan module? How would that affect increase and fluctuating RPMs?

Howdy. I think, just as noted, your fans running more often is not right...especially with it being winter, assuming you're in North America.

If the fan is constantly running, then the fans are having a cooling effect on your engine. It's not as efficient as the cooling effect of the coolant in the radiator, but still cooling nevertheless.
Generally an engine that's too cold isn't good for emissions, and the computer will try to rev it higher to get up to temperature for both the engine & catalysts. Watch cold startups to note that the RPMs are usually higher than idle for a brief moment.


However, you also have the code to go by. P0171
The car sees your fuel injection system as being too lean. It will thus compensate by adding fuel, which makes the engine rev higher.
Hence my thought to focus on the MAF sensor, intake tube & PCV system leaks, with a possibility of the oxygen sensor actually being bad - a code that doesn't usually cure itself.

The cooling fan module is just an elimination step. You can test it by putting your car into ACC then ON mode (without turning the engine on by brake). If the fan runs then there's an issue.

Appreciate your response. I live in North Georgia so it gets cold in the winter. First think I’ll do is change out the Cooling fan module. As I mentioned the Cooling fan module was changed out at 87000. 99000 on the clock now. Would you order an install the same module (Beck/Arnley 203-0276) that a previous post recommended to me or go OEM INFINITI or local parts store. I think most of these parts are made in China which might contribute to an earlier failure? Appreciate ya.

I wouldn't hesitate to buy a Beck & Arnley unit, although OEM would be best. However, buying either brand would be a waste of money unless you've tested & isolated that as the issue.
It's simple to do that. And also check your coolant level while at it.

My suspicion lies on the intake leaks, but as usual, I prefer to troubleshoot & test the simple things first.

Thanks. Will troubleshoot cooling fan module first and report back on results.

EdBwoy ran cooling fan module test as you described above. Fan does not run at cold startup when moving from ACC to ON. It doesn't run when you initially start up either but my take is that the fan runs more than it should during driving. Its always running when I stop to go to the store or when I'm pulling into the garage. It's hard to believe the module is bad considering it was replaced 2/2018 but I guess its possible. Any thoughts?

Update: just ran out to the store. fan was running when I started M after shopping. Pulled into another store to pick up some Bourbon fan was running. Left the car running and when I came out fan was still running. It's cold and rainy in North Georgia. No way the fan should be running this much. I'm thinking about changing out the module. Infinitipartsonline whats $90.00. That's twice the price of the (Beck/Arnley 203-0276) module. Should I change out the module and go with Infiniti part? Appreciate ya.

The modules fail in one or 2 ways that I've seen:
1. Constantly running as soon as the pushbutton is engaged
2. Delays to turn on at startup (like normal), but never seems to turn off until the engine is shut off and cools down.
Sometimes this is a response to coolant level. I had suggested you look at that as well - have you checked the reservoir and radiator/ filler neck level?

Is the initial idle issue still ongoing?

I want to be clear that the fan module was just a troubleshooting step. I'd hate for you to spend money on a new module and end up in the same position (I mean, you'd end up with a functional spare so that's cool I suppose)

I did check coolant level and it is perfect. Sorry for not mentioning. Upper and lower hoses were replaced with coolant on 07/2018. #2 of your previous post is the condition that I am experiencing. I believe what I'm seeing is cooling of operating temperature that should not be happening but I'm no auto expert. If I go for the module should I get the one from Infiniti (Part Number: 21493-4GA0A) at partsinfinitiusa or order the (Beck/Arnley 203-0276) module. Thanks for your help.

In that case, I'd go for the Infiniti part and see if things get better.
The Back & Arnley part might have some sort of a warranty, but the constant replacement can become a nuisance.

FYI, I've seen the same OEM part with way better prices - prices that make it that much better to just buy even as a troubleshooting step; for example https://www.infinitioepartsdirect.com/o ... 214934ga0a

Edbwoy thanks. You rock. That’s a much better price at this point for the INFINITI part. I will order, install. And report back on results and next steps as necessary. Appreciate ya.

Just received today and installed Infiniti Infiniti (Part Number: 21493-4GA0A) cooling fan module. Fan is no longer running and idle rpm is back to normal. Looks like the new module resolved the issue.

Thanks for the update gav'. I'm glad the issue is handled for now.

I suppose that's another component we should encourage people to buy OEM only, especially with such low prices.

EdBwoy taking the M in for OEM platinum plug and pvc replacement. Just rounded 100,000 on the clock. Let you know if they find anything else.

Yeah. I was just going to add to what these guys are saying. From an engineering standpoint, higher RPM is a result of more fuel and air. Fuel will match the amount of air entering the engine to stabilize operation. Check that throttle body assemble for excessive debris that may be causing the plate to stick open, even just a little bit.

Thanks. I will have the throttle body assembly checked out for a cleaning as necessary when it goes in for plugs and pcv replacement. It may be my imagination but the OEM part (Part Number: 21493-4GA0A) seemed to be better manufactured than the (Beck/Arnley 203-0276) module I installed 2 years ago.

I bought the beck arnley part.Usually they make good parts..went on a four hour trip out of town and the fans weren’t running when I got to stop lights and were idling..car start overheating and ecuador was raising the idle. I open the hood and replaced the beck arnley with my old oem fan module that luckily i had laying in the trunk..it was defective but atleast the fans would run all the time even if they were running constantly

Another trick you can do is to buy the part from a G37, Juke,M37, etc and use that. It is the updated part number and is the newer part than ours. Shouldnt fail or anything like our old part number part.