hey guys I have a 96 civic hatch with a b18c. it is an obd1 conversion with a p72 ecu that is stock. The problem i am having is when the operating temp. is cold the motor runs fantastic but once it gets up to normal operating temp. i start to get a misfire around 3,000 rpm that last until over 5,000 rpm. it is intermittent and really seems to happen only when cruising and sometimes when pulling away from a stop. the wierd thing is it seems to only happen when the weather is cold the warmer the day the less it does it. I am getting about 19mpg which i thought was a little crappy but not bad i guess. i have replaced fuel filter dizzy cap and rotor, O2 sensor, plugs wires. it didn't have an IAT sensor but i replaced that. Any ideas out there?