Why would the MAF sensor fail about every six months? What could cause this? I've checked the wiring, connectors and everything else I can think of. It does not look oily or dirty. On number three and it's out after six months. Number two lasted two months, thought it was just a bad one. When number one first started showing signs of failure we cleaned it, and it seemed OK for a while. Then CEL came on and were still at it. Al