Erratic AFR's at WOT only
 

Can any one tell if this is a spark blow out related issue by looking at the log? The AFR's swing at least 2 points when all the values are pretty similar in the load/rpm range used at WOT

Car information:
1.6L 4G92 Mivec motor
Evo 8 Ecu & MAFconversion
Evo 3 510cc injectors (i have proper size and scaling in)
Custom 3" intake
4-1 headers & 2 3/8" exhaust
AEM Wideband

I have copied over the stock ignition tables and I am mostly knock free (1-2 count low down).

I am only using the low cams (think VTEC) at the moment as to not complicate matters.

I have lean spool turned off and am using the AEM to emulate the narrow band signal to the stock ecu. Closed loop is no problem, car drives around fine and idles perfectly.

At first I thought it was the injector scalings i had wrong so i swapped the stock ones out for the Evo 3 injectors which I know are correct.

The car was running fine on the stock ecu until it crapped out.

I am changing out to fresh plugs and plug wires later on but any insight would be much appreciated.

Well I have tried the following:

New BKR7ES plugs gapped to 0.9mm or 0.035"
New FIC fuel filter
AEM AFPR
Swapped coil packs


The only thing I have not changed are the spark plug wires.

Also the valve cover vent line that ran to the stock intake is just vented to atmosphere now, essentially that is a boost leak. I am hoping that could cause this. I will be welding a bung to the intake tomorrow. I will report back.

connected the valve cover vent to the intake, no change.

I am stumped.