Throttle cuts out when accelerating.
 

91 miata 1.8l swap
I have an issue, where the car will start to miss, then be completely unresponsive to the throttle for 10 to 15 seconds. Starts to stumble(misfire) while trying to accelerate for another 30 sec or so. Then will clear up and run fine. Usually at highway speed. Only on warm days and once engine is at operating temp. I have no clue where to look since its only does it the interstate.