My Trooper's mileage seems to be getting worse. It has 120K miles on the
clock, and AFAIK oxygen sensors have never been replaced (been driving it
since 98K). I'm thinking about replacing O2 sensors - how long exactly are
those supposed to last? Also, Alldata shows sensor's pigtail being kinda
round, but all sensors I've been able to find online have rectangular plug
type. Does that mean I'll have to splice the wires and re-use existing plug?