m3 e46 inconsistent power!

[zainm3]

So I have been having an issue were the power keeps on dropping in the M
The other night had a few runs (track) and on a roll only managed to stick with a stock e46 M and slightly moded e36
So the next day I put it on the same dyno I use and it was down by 40KW ! Only pushing out 202kw fly
So we tried an air flow sensor from another M and straight up it jumped by 18kw
What I need to know is, is the afm my only problem could it be something else ,can the air flow really cause the inconsistency ? And what do I do if the prob continues I did order a knew afm now

 

[M3_FTW]

It is the AFM. Because the E46 M3 runs a maf (unlike the E90/92) if the MAF is stuffed it gets incorrect air flow readings. Then drops the fuel/ratio to suit.

 

[zainm3]

Thanks m3 ftw busy working on that hope the car gets back to were it was and stays there