LOW idle

Like really low idle. The needle sits right above 500. Just got a new timing belt and water pump. Timing is right. I give it some gas and it would just bog or gas it slowly and it will climb up. I put it into first, moves off then idle drop back down to 500-600 rpm. Car was done at school and can't leave the campus. Could it be the map sensor(I have like 3 spare ones at home) or iacv?
Motor is b18b1
Ecu is obd1 LS ecu forgot which one exaclty
Motor is b18b1
Ecu is obd1 LS ecu forgot which one exaclty