Ok as suggested by a few people I'm making a post for this problem, Mods if wrong section sorry, please move it need be.
Ok it has been doing it since I bought the car, I thought I could "live with it" but I am getting very picky with the way my car runs @ all rpm.
Problem: When driving (or free revving up down or up hold then let off). When I let off the the gas the car will swing to a very lean afr 19-20 on lm1 then sing back to the rich side hitting around 13.9. The rpm's will drop very low under 500. after a few swings the rpm & afr's will too, then a huge puff of over rich smoke will roll from the exh. the car had stalled from this on many occasions. Now if I gradually allow the rpms to drop comming to stop the car will not do this, only when the throttle gets rapid inputs. At the time the afr goes nuts with rpm the inj. pw will drop to 0 then swing back to 4.xx ms..
I have done the conversion to my rom so that the maf reads in Hz and played with it for several hours tonight but the car still does it. I finally gave it up and ret. to the stock maf settings. I also thought perhaps the IAC motor was bad so I pulled that and ohm checked it, cleaned it, reinstalled, helped a little my steps went from 80+ to 73.
Mods on car:
sun auto hyper force, hyper voltage gt, ets fmic 3.5 inch, 3 in tbe, wal. 255 fp (stock injectors), evo 9 turbo, crappy intake pipe that was on the car when I got it weapon R off turbo to maf, custom 4 inch in fender after maf (yes I know I should ditch the WR intake .) 9 MR bov, sneaky peat meth. this problem existed before the infender after maf section.
This is driving me CRAZY help is much appricated.

 

This is a pretty well known problem. The root cause in most cases is simply that fact that we have a MAF based system and when you mod parts like the intake pipe, filter, or turbo that can screw up the signal, things like this begin to happen.

Specifically, what I have seen when helping someone with the problem is that the MAF overreads for a split second when letting off throttle. The MAF is still reading airflow when there is none.

There are ways to try to make this better, like setting your idle correctly usnig the SAS/BISS to ensure your stepper motor has the proper range of control, scaling the maf, playing with injector latency/scaling, but the best way to fix it while still sticking with the MAF is simply to remove the mod that is causing the most problem. In your case, it's most likely the intake pipe.

Other than that, there are patches being written currently (and one that evoredy already posted) that will emulate your MAF signal from MAP, so that these erroneous airflow readings will not occur. You can try that patch as a possible solution as well, or wait until tephra/mrfred.jcsbanks/acumus, etc are done researching and writing a full-blown SD patch.

 

thanks, after playing with the scaling for a few hours each direction I was dead set that it was the weapon R hard pipe off the turbo I might try a stock rubber one and see results.

 

bev/evoredy map to maf patch can't drive my car without it