[mkiv] Rich idle AFR

[Alex Gregory]

I have been having a strange problem with my idle.  I have an VPC/GCC
combo with stock fuel pump, BoostLogic fuel rail, fuel dampener bypass,
Aeromotive FPR and Siemens 75# (780cc injectors).  I still have the
factory 9/12V ECU in for the fuel pump installed as well.  My car is a
1994 single turbo (T-61).

The problem is that my AFR at idle is ~12.0.  I can adjust the idle
screw on the VPC from the 0 position to full lean, to lean it out to
~14.7 but then I get a stumble when revving at about 1500.  Makes starts
kind of annoying.  I checked fuel pressure and it is 28lbs with the host
connected and 36lbs with the hose disconnected.  When cruising it is at
14.7 right where its supposed to be.  As long as its rich it drives
great it just stinks a bit.  Does anyone have any ideas why I am rich at
idle or why I get the stumble when I lean it out?  Should I just leave
it alone if its behaving correctly (drivability wise)?

Thanks,

Alex G.
91' Syclone #411/2998
94' T-61 MKIV Supra
04' V70R 6-Speed
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