hey my brother just bought an 89 prelude with fuel injection and it has some issues.

the first issue is that it has a connector unplugged on the front of the intake manifold with two prongs. the thing the connector is on has a line from the throttle body to it and has another one that looks like it goes to the block. when it's unplugged the car idles fine, and when its plugged in it idles at 3k rpm but it seems like it has a bit more power. we can't find out what this thing is in the repair manual.

the second problem is that under hard acceleration, the car stops making all power for a second then kicks back in for a second, and then stops again and repeats. there are no check engine lights on or anything so we have no idea what the problem is, can anybody help?