Plugs.......

 

I had the EXACT same symptoms as you...It was my MAF. Like at light throttle the car is OK...but if you push into boost in stumbles. Here is a quick way to diagnose if it is the MAF. Just unplug the maf (takes like 2 seconds) and drive the car with just a little boost and see if it is normal. If it is normal the MAF is the culprit......when you unplug it goes to default settings.

 

Hi all, FYI, the shop says it was the MAF, needing replacement.
I will pick the car up in time for the SCCA nationals at Atwater
and will let you all know whether there is any return of the
problem!
Joe

 

good luck at the nationals man!

 

sounds like he solved it, but the MAF can definitely cause performance/driving issues...hesitations, stumbling a bit, etc.

BTW - how much did they stick you for to replace the MAF sensor? cleaning it is a decent option too...just FYI.

 

I have yet to see a blown MAF brought back to life with cleaning...this is a myth. You can get MAFs on-line here:
MAF

 

The best place I have found for stock 996TT MAF's
www.dps-motorsports.com"
$239.00 + $9.00 shipping
You need to contact them, they don't show them on their web-site.
I hope this will save someone some $$

 

perhaps it depends on how messed up it is, or possibly its just a bandaid solution, but i can say for sure that i was getting slight hesitation at partial throttle (like real partial, cruising on the highway style foot barely on the gas) that was kinda annoying and had even thrown a weird code (cant remember what it was right this sec), but i cleaned the sensor real well and all that is gone.
I assume i will have to replace it soon either way, but i had the issue on a weekend and wanted to drive, so band aid or not, it worked for me.

 

had maf probs felt just like plugs tru your maf 1st it's cheaper... i had no cells just the feel you discribed, nad not consistant.... made the mistake of checking my maf last, check it ist easy fix good luck

 

cleaned mine it woorked for 6 months (very well)

 

OK team, the MAF fix seems to have done it. The shop
charged me $400 for the MAF, and 2 hours to diagnose
it. The nationals were a big deal. Saturday started out
wet with a light rain, but dried by the end. AWD got me
to within 0.1 seconds of the lead after the first run, but
in the dry the DOT tire guys took over (I'm racing in a
true street tire class). Sunday was all dry, and I started
at about .005 seconds behind my main class competition,
and we swapped leads for the first two runs, and both
screwed our third runs. I beat him by more than he beat
me so I got the overall win!

 

Congrats !!!

Very nice use of car.

MK

 

Thanks Woodtster! It's be a sin to own what is arguably the
best sports car in the world, ever, and not get the max out
of it. For the first four years I owned it I kept *all* records
including every receipt for all gas put in the car. I went over
them and for the first 13,000 miles overall, I averaged 8 MPG
Joe

 

I'll ask the question here, as it seems to have a good roster of subscribed members...

MAFs are a consumable- over time you get fouling of the sensor and a gradual degradation of the signal. Eventually the AFR is shot and a CEL is triggered when the DME can no longer adjust to keep the mixture within range (I think- this is my experience with the M5)

Is there a way to read real time fuel flow numbers via the OBDC? On the E39 M5 one can 'unlock' the display to get a real time display of instantaneous fuel delivery in L/hr. This almost direcly correlates to MAF health...

CELs with random misfire causes, stumbles at certain rpms, the 'limp home mode', or just low power without other failures are often MAF related.

We're not talking 'blown mafs', more like tired mafs...

So, my question- is there a similar function on the 996?

A

PS Nice work Joe.

PPS Steve- CRC maf cleaner works for a while, but you get oxidization that cannot be remvoed with solvents eventually

 

Not to my knowledge, you can hook-up several programs and get this info real time, like durametric.