Agreed.
I am no genius or mechanic but in my mind the bigger cams increase flow in the head not at the MAFS, so the ECU would not see an increase in flow coming in from the MAFS but rather a leaner mix going out at the O2 sensor… and we all know how crap the stock narrowband O2 sensors are. Considering my narrowband A/F guage was reading rich at WOT from 2000RPM to redline but the truth of the matter was that while Dan was tuning my SR the actual A/F’s were reading 16.0 at 4000RPM which is really lean.
Anyways,
Check for a boost leak after the MAFS.
Try a different MAFS rather than just cleaning yours.
Try another SR ECU. a buddy of mine had an SR running like shit and it ended up being the ECU, after further inspection inside we found a cracked and faulty solder point.
Check all your injectors! i had a leaking injector and it caused my motor to run richer, not by a whole lot but it was a factor
Check all the basics and try new parts on all the basics. If you have any other friends with an SR spend a saturday morning and try parts from their SR on yours until you find the problem. Things like FPR, MAFS, injectors, Spark plugs and coils can all be swapped back and forth easily.
Come to Mississauga and I’ll help you out even!
Good luck and keep us posted!