Gilly and MB Doc
thanks for the comments. I plugged the wire back in the same sequence as they were taken out. As to the MAF sensor, I took a peep at it and I just could understand why it cost so much. There's just a small pcb board with a few chips soldered on it. Anyhow, the ECU is still learning the tricks after I pull the battery cable. Will see if the check engine light ever comes back.