I almost gaurentee its not the ECU. I would say its an issue with a bad sensor or wiring.
If it was the ecu, it wouldn't be a spot in the range, it would be the whole cha-bang. Sensors can and will provide bad data at certain points (especially transducers like your map sensor), wiring can pick up and weird shit and cause issues with components through inductance, poor insulation, poor contact etc.
I'd say there's about a 5% chance its the ecu and I mess with shit like this all day long tracking down problems in electrical systems a lot more advanced than an automobile.
Its probably something fucking stupid like a lose pin imho.