Stock 93 v6 dyno run

[Bluecam6]

I ran my 93 v6 carmy wagon 189000 miles etc, sunday just for fun. It made 136hp at 5400rpm and 152lbs of torque at 4100rpm. Does anyone know why the toyota engineers programmed the engine ecu to run very
rich air fuel ratio above 3000 rpm. Its af was 10.3 at 6200 rpm??????????????

[Bluecam6]

The af at 3200 rpm was 14.4 then at 4100 the af was 12.8 and then at 5700 the af was 10.8 ........... Toyota must have a reason that they programmed
the fuel mapping very rich above 3200 rpm. If i compare this to 89 camry v6, my 89 has a af of 15.0 at 3200 rpm and 13.3 at 5200 rpm.......?????

[Bluecam6]

I also advanced the timing to 20 degrees and that didn't make any hp gains.
I diconnected the vaccum control that control the volume of air inside the intake plenum located on the passenger side of the engine and that didn't
gain any hp. The best gain was from putting a very large fan in front of the car to cool the air going into the plastic oem air filter box. That made a 7hp increase for 24 degrees of cooler air temp........The air temp at the air filter was 57 degrees.....................................