Originally posted by DarkOne
It could also be the MAP sensor. You said you installed an FCD first, can you verify the MAP wiring was reconnected properly and you're actually seeing a MAP signal at the ECU? Look for the yellow wire / black stripe in the ECU harness. Start the car, let it idle, and test with a voltmeter that you're seeing ~4.0V+ on this wire.
try that ^^^ too