I did search, I found a couple Infiniti specific threads but am interested in started a new thread specific to cleaning the MAF in a VQHR dual throttle body dual MAF engine.

I have almost 77k miles. recently at 69k I received new throttle bodies and a new ECU right after a spark plug change.

My fuel economy has dropped down to high of 21 and low of 17. I used to return low 20's. I also have a rolling start stumble that presents about 70% of the time. About 20% of the time at WOT the engine sounds/feels lean and I am forced to lift off the throttle to get a good 1-2 or 2-3 shift.

My dealership performed many many test using the consol tool about 1000 miles ago and I have no check engine lights or malfunction lights.

To me it feels like at high rpm sometimes and low rpm sometimes the engine is fuel starved/lean. I suspect that the MAF sensors are dirty and not returning an accurate reading at the extreme ends of their service range.

What is the best way to clean them? I had supposed that Saturday night after 24 hours of not using the car I would carefully remove them and use MAF cleaner from and auto parts store. I would then re install them the next Sunday morning and not drive the car again until Monday morning.

Techs what do you think? I know new MAF's can run over $1,000 so I want to be careful!

Thanks,

Jeff

video of shudder/stumble

Shudder in drive you can see the tach drop but my foot is still on the peddal



Shudder in reverse you can see the tach drop



I should add that I have Fujita shortram airfilters and about once a month run Lucas fuel additive.

Jeff,

I'm not a tech guy but I would use rubbing alcohol to clean it.

But I'm sure the tech guys have better solution.

Does it happen in DS also or it is only in D?

I have on multiple occasions cleaned MAF sensors on my G and friends vehicles.

I just use the CRC fluid, making sure to keep the spray nozzle 12 inches or more from the MAF itself.

Never had any problems.

from my Nico research I know that you DO NOT want to actually touch the MAF with anything but liquid. The MAF has a electical wire as thick as a human hair that makes it work if you disrupt this wire the MAF is trash.

I was planning on using the CRC MAF cleaner and giving it plenty of time to dry.

Its been about 10,000 miles since this issue started and it is not getting better or worse so it must be electrical. Mechanical would have gotten worse or failed. It happens in D DS R and 1st. It feels like the engine is fuel or air starved for just a second and then the power comes back. It does not happen all the time maybe 1 in every 5 part throttle starts.

Thanks for the replies guys. I'm hoping Steve the Tech or Poyzinous will reply nudge nudge. If I kill my MAFs this will be my last post when my wife finds out

hahahah

You G might need to learn the fuel air ratio.

Let see what they have to say about it.

Poyzi, Steve where are you?

just get the CRC and clean it as directed on the bottle...

like you said, be sure not to touch the wire/resistors or anything

First guess, then questions

Have the dealer set the exhaust timing learning procedure. This is found by selecting the repair button on the CIII menu and selecting electronic repair, the thing that gets people is that under Work Support this is on the second screen due to size limitations. That would be my first guess as this usually needs to be set with several other initialization procedures on all new ecms.

As for your fuel econ drops, the last ecm has 7x,000 miles to establish a long term base timing schedule that returned your numbers. This may actually take several thousand miles to reset. However this is another small red flag to me that one of the base parameters is not set.

gwoods wrote:I have almost 77k miles. recently at 69k I received new throttle bodies and a new ECU right after a spark plug change.

WTH happened there.

SteveTheTech wrote:WTH happened there.

I'll tell you off line all I can say is never ever never ever clean your throttle bodies!

Thanks for the tip!

gwoods wrote:from my Nico research I know that you DO NOT want to actually touch the MAF with anything but liquid. The MAF has a electical wire as thick as a human hair that makes it work if you disrupt this wire the MAF is trash.

I was planning on using the CRC MAF cleaner and giving it plenty of time to dry.

The newer MAFs are not as fragile as they used to be. The hot wire is still thin but it stronger. I see bugs get lodged in there frequently and the usually just burn up.

I still don't think mafs are your issue although.

If I were you I would shy away from maf cleaner with a consistency of contact cleaner. Compressed air cans work perfectly. If you have something suitable clean the wires and blow them dry. Check the voltage reference if you want to actually see whats up before pulling them. It's not that simple anymore.

I came across this thread doing a search on cleaning the MAF. I have a 2007 G35 Journey sedan with the dual TB's and am experiencing the same exact problem the OP states here in addition to some surging at light throttle below 2000 rpm (pretty sure only below 2k as it seems to be ok above it). My problems only occur while the engine/transmission/MAF's are warming up. Once it's been driven for 15 minutes or so it is smooth. I can't say anything about WOT since I haven't gone there yet. I bought the car with 94,xxx miles and it is at 105,xxx now. Problem started ~2-3k miles ago.

SteveTheTech, any input on this? I've gone through the accelerator pedal release position learning and am pretty certain I did the idle air learning correctly along with the TB valve learning, but no change.

GWoods, did you resolve your issue? I don't see a post with a fix.

I cleaned mine this fall when I replaced the spark plugs. I simply removed the 4 bolts to free them and I did NOT disconnect anything. I sprayed MAF cleaner and used a terry towel to wipe all the carbon out (I did not move the butterfly at all). I also sprayed a bit into the upper plenum and wiped that out as well.

I had no issues afterward.

tjrob2000 wrote:I came across this thread doing a search on cleaning the MAF. I have a 2007 G35 Journey sedan with the dual TB's and am experiencing the same exact problem the OP states here in addition to some surging at light throttle below 2000 rpm (pretty sure only below 2k as it seems to be ok above it). My problems only occur while the engine/transmission/MAF's are warming up. Once it's been driven for 15 minutes or so it is smooth. I can't say anything about WOT since I haven't gone there yet. I bought the car with 94,xxx miles and it is at 105,xxx now. Problem started ~2-3k miles ago.

SteveTheTech, any input on this? I've gone through the accelerator pedal release position learning and am pretty certain I did the idle air learning correctly along with the TB valve learning, but no change.

GWoods, did you resolve your issue? I don't see a post with a fix.

Other things that can cause surging is timing and injectors as well.