I installed a Tomei ECU, and I noticed a big difference in the throttle response. Let say I'm ideling at 1000rpm. If I blip the throttle pedal briefly, the engine used to rev up to 2000rpm and fall right back immediately. Now when I do that, it revs up and stays flat at 2000rpm for at least one second before falling, my foot is completly off the gas.

Do you think the Ecu is programed to hold rev longer? The car does feel a lot faster between 3000-8000rpm, but now I am paying US$0.3/km comparing to US$0.25/km. what's done to the a/f ratio and ignition timing?