Mt 1999 Trooper 3.5 with under 50,000 miles has developed an idle that fluctuates and some times refuses to return to idle, staying at about
2200 rpm when coming off throttle to coast or stop. The code comes up as lean mixture oxygen sensors. anyone else have this problem? Automatic transmission. Ron
What code number(s) exactly are you getting? There is whole slew of them, and there are 4 oxy sensors in that vehicle.
Wild guess: check your intake manifold gasket. Mine just went at 130K miles, but others have experienced it to fail much earlier.
Peter
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