During our testing we discovered a disparity between identical Camaros in terms of there reaction to changes in airflow and weather conditions.
We noticed that one car would be finicky at cold start and the MAF would scale "weak" while others would be strong and clean.
What we discovered was that the 'WEAK" meters were reading 1560-1670HZ at idle with the A/C off (OEM is 1800MHZ+)
During on road, light throttle input the MHZ would be slow and weak to respond to throttle changes (hesitation)
Wide open throttle showed 120-170MHZ lower than OEM stock (OEM is about 8600MHZ) on the same car.
Weak Meter Fuel trims-
The fuel trims would go to -15% using a VR -3% for a panel filter and -5-8% for other intakes. MHZ would drop as would the idle. When the MAF scaled in at WOT each would richen up accordingly.
Test 2 we pulled the filter from the VR completely, this resulted in fuel trims dropping down from -15% to -24%, MHZ dropped another 70-90MHZ. The car would drive fine but WOT operation was basically weak/flat and timing was low etc...
Now with one simple meter swap which takes about 1min the car immediately corrected, went back to 0% fuel trim MHZ jumped back to 1800+ all within 30 seconds! The car drove like a Rocket!
We began final confirmation by swapping air meters in cars and doing volt meter testing in static conditions. 30 meters, 3 cars = the same exact result every time. We confirmed this with VR customers tuners around the US.
The Result is that these 'weak" meters are not showing the same resistance levels as the majority of OEM meters.
This lead us to contact the GM rep and the actual manufacturer of the meters (its not Dephi) They confirmed the factory which allow us to identify each meter.
These numbers and letters are located on the back of the meter as shown.
(WHAT TO LOOK FOR) The factory code
The suspect meters have all consistantly had a single letter located in this area VS a number with a letter.
Here is the catch 22
If the airflow is not changed by a substantial amount (our flow testing verifies that most of the aftermarket boxes do not) over OEM then the meter will be within OEM Tolerance but will always be "weak"
you cannot tune this out, its a fundamental issue with the resistance of the meter. It needs to be replaced. This is why some cars are finiky and some are not.
We have made arrangements through our GM parts dealer to stock meters just for this purpose.
We will be selling them at our cost (no markup at all)
You may not need the meter, estimated 90% will not.
"This meter is also used in the Corvette as well and some of those as of 2010's are starting show up"