either map sensor or vacuum leak.

reset the ecm, then start the car. using the throttle, keep the idle at 1000 RPM for one minute.

if the light does not come back on, it's the map sensor. check for a broken/loose connector. if it's secure, try swapping the old sensor to the new engine.

if the light does come on after holding the engine at 1000 rpm for a minute, check for loose vacuum lines.