adlee3

Hello,


I had posted my problem earlier, but seems as if no one was able to help. I have also gone to two mechanics and two dealerships.

2008 Infiniti G37s - Automatic - About 60,000

WHEN

The problem occurs only after I drive for more than 20 minutes (after the car warms up), and only if I drive locally for 20 minutes. Even if I drive 3 hours on the highway, the problem will not occur until I have driven it locally for at least 20 minutes. A mechanic told me that the internal temperature is much higher during local driving, which would explain why it happens when the vehicle is warm. The problem also goes away if I turn the car off and let it cool back down.


WHAT

My normal RPM at idle will be around 750. When the problems start occurring, the idle will shoot up to 900-1000. The idle doesn't move around but has almost a permanent increase. The MAIN problem is when I drive in manual mode and accelerate from a stop, the rpm will go up fast and the car will accelerate, PAUSE at 1500-1700 and then start going up again "slowly." This is only noticeable if I am at the front of traffic at a red light. If I am in traffic, driving slowly seems to hide the issue. ALSO, driving it in Chicago rush hour doesn't make the problem occur as much, because all I am doing is braking and letting go. But after driving it in the burbs, it will always appear.


QUESTION

The dealership took a look at it overnight, and found that some of the readings were off for the mass airflow sensors. They said it wasn't enough to throw a code, but enough to cause my symptoms. They quoted me about 800 dollars to replace them. They did say that it was a "really good estimate" to what the problem might be, but couldn't guarantee any fix. They told me they would of course make it right by perhaps not charging me for any additional fees if it didn't solve the problem. BUT, that basically means that if I want them to fix it, it WILL cost me 800 or more.

Do you guys think based on my symptoms it is most likely the mass airflow sensors? Every mechanic and service adviser has told me that it probably doesn't have to do with anything like coils, spark plugs, fuel pump, arching, vacuum leaks, etc. From ALL the things I have read for the past month, I don't think anybody has fixed a similar problem by replacing the mass airflow sensors. They did it by fixing cheaper things like the above mentioned items.

Is my case just really unique? I would hope that it isn't the case.


Thanks in advance!

TVPostSound

iTrader: (9)

What? No warranty??

If $800 MAFS don't fix the problem, they need to remove them and not charge you until they find the problem!!

Rad_Slinger

iTrader: (12)

could always try cleaning the MAFs yourself. see if that remidy's the problem.

if not, don't let them charge you 8 bills to unscrew 4 screws and replace them. order them and replace them yourself. would take all of 3 minutes to do it. probably cost you $200 less.

adlee3

TVPostSound: I forgot to mention. I did have both my throttle bodies replaced under warranty, but that didn't fix the problem. The MAFS aren't covered under the powertrain warranty, which is the only one I have left. And I highly doubt they will replace the MAFS and then not charge me if it doesn't fix the problem.

Rad_Slinger: I did try to clean the throttle bodies a few weeks ago, but I couldn't get the screws off, they were really tight. I assume the MAFS would result in the same thing? I'm not sure if they meant that my MAFS were going bad or if something was off with the "computer." There was a mechanic I talked to who used to work alot of with Nissan cars, and told me that the MAFS would go bad even under 100,000 miles.

Thanks for your responses!

TheLocNar

iTrader: (5)

You can do this yourself. Don't worry. It's easy. Get 2 new MAFs at the parts department. Drive home. Unscrew/unclip old ones. Put new ones in. 5 minute job at the most. Hopefully that's actually the problem. Good luck!

TVPostSound

iTrader: (9)

They replace the MAFs per THEIR recommendation, if it doesnt fix it, they remove the MAFs due to their wrong diagnosis.

Why pay someone to guess, and replace arbitrary parts!!

You can always do what F . U. C. K. ^^^says!!

adlee3

I do have a question. I was looking up MAFS on advanced auto parts and other websites as well. I noticed that there was the actual "tube" thing which showed up sometimes when I searched for "mass airflow sensor." Other times, I would only get a thin "chip" that would fit into the "tube" thing. I guess my question is, which one is the actual Mass Air Flow Sensor? My dealership told me I had to replace both my mass air flow sensors. Does that mean I have to replace the "tube" part of the "computer chip." Or both...

OB G

iTrader: (11)

I think the tube thing you're referring to is the intake. The MAF sensor is chip thing that you're referring to that goes in perpendicular to the tube. Looks kinda like this:

http://s3.amazonaws.com/fcp-product-...jpg?1291305755

Oh and from the looks of that link, they're *only* $100/sensor. A lot cheaper than what the stealership wants to charge you.

adlee3

Update!

so I ended up just disconnecting both mass air flow sensors, and then replugging them back in, and what do you know. The hesitation I described seems to have disappeared. However, my idle seems to have permanently decided to stay at 900 whether it's warm or cold. The hesitation is pretty much gone, but it seems that I still sort of lose power after the car warms up.

I think that I might have either switched the mass air flow sensors, and put them into the wrong sides, or just taking them out and putting them back in might have done something. Would switching the two mass air flow sensors cause this?

I can certainly live with the unnoticeable hesitation, but I'm assuming I definitely might still need new mass air flow sensors. also, my cel is on now, even after i put the mafs back in.

Thank you all for you help!

TVPostSound

iTrader: (9)

Get a can of "MAF spray cleaner", its similar to carb cleaner, and brakekleen, but meant for MAFs.

Remove your MAFs, and spray where the airflow hits the "sensor wire". make sure to replace the MAFs with the sensor wire pointing into the "wind". (Where the airflow would hit the sensor wire.)
Disconnect the battery overnight, and see if the ECU can relearn.

Make sure the orings on the MAFs are still there!!

adlee3

i do want to clear the cel. but i want to make sure that it's not on because i did something to the mafs. if you put them back in, should the cel go back off?

and based on what exactly i did today, does that most likely mean that my mafs are wack? considering that working on them slightly could cause such an improvement in the smoothness of the driving? removing them obviously made things worse and my car could barely rev, but after i put them back in, performance completely changed, for the better.

i'm not really questioning if i should clean them or not, because that would only be a 6 dollar investment. one i don't need to think much about.

but i am wondering if i really did "fix" the problem. or if i still need new mafs, because i just did a better job of hiding the symptoms.


thanks!

deep007

I have two extra mass air flow sensor came off my 10 g37 with 18k miles on them. I don't know if your still looking wanted to buy them. Make me a offer I can sell them for dirt cheap.

TVPostSound

iTrader: (9)

Did you even try to clean them???

adlee3

i'm not sure what price to even begin at. but i'm not planning on changing them anytime soon, because the hesitation is pretty much gone, and the symptoms are bearable now compared to before.

and yes i did clean them as i mentioned that it wasn't even a question considering that it was only a 6 dollar investment. didn't do much to solve the problem.

and like i asked before, i would just like to know if my cel light should have gone back off after putting the mafs back in. they weren't on before. and although my hesitation is gone or almost gone, my idle now shoots up to 950 regardless of if my engine is cold or hot. and i'm aware that you can "clear" the codes yourself. but i want to know if the cel is on because something is wrong? or just because i took the mafs out and put them back in.

Rad_Slinger

iTrader: (12)

Might need an idle relearn to be done now the issue has somewhat resolved. Or throttle position reset as well.

There's a DIY on here or you can go to any Infiniti dealer and have it done pretty cheap.


Also....now the problem is somewhat resolved, clear the cel by unplugging the battery for a few hours and see if it comes back on. If it does, take it to the dealer and have them do the relearned, clear the cel, and see if it comes back.

Only thing I think you can do.


And yes, the cel might have triggered if you unplugged your MAF without disconnecting the battery OR something is wrong.


Try to clear the cel now the problem is resolved and see if it comes back....then go from there.