Having a idle issue with monte ever since I installed plogs and deleted my egr valve and block the exhaust and intake with maf plugged car cranks and revs up and down almost cutting off then it levels out after warming up get about 22 mpg Ltft 16.4 stft 20.3 without the maf sensor stft 0 ltft like 8 car runs smoothly if not better on acceleration but mpg is 18-19 changed maf sensor and cleaned out of 2 1 worked I noticed that my maf sensor was different if I believe right for the hen v swap I got it off of a regal used the blower adapter plate and the TB but I might of swapped tb with my stock one or one I had laying around but I seem to keep running across 2 different maf sensors found them.on both n/a and s/c engines 3.8 series 2

This is the sensor i have on my car only found on regals and 97-98 grand prix

When pulling out the sensor out of most l67 found this sensor in the l36 to

 

The MAF is not different between L67 and :36 (SC vs non-SC). It's the same sensor, the tuning for it in the PCM is different.

I'm not 100% clear on your issue. During the Series II era, GM has a different throttle body for L67 and L36, but they ALSO changed those throttle bodies late 90's/early 2000's. One has a MAF "bridge" (early design, there is a post the goes from the top of the throttle body to the bottom) and the other has a MAF "hump" (later design). I attached are pics of both. And the MAF sensors vary depending on which design you have. In addition, I would speculate the tuning also differs based on the design being used.