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Q: Trouble running when the engine warms up, dash lights on - 2007 Subaru B9 Tribeca

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The dashboard in my car has lately been showing the Check Engine Light illuminated along with the cruise control light and VDC light on. The car has no issues running when the engine is cold or a bit warmed up. However, after I have driven for a couple of hours, it has struggle developing speed. At that point, I have to get the engine cooled down maybe even several times during driving, depending on the distance. I went to the dealership but they requested me to leave the car there so that they could diagnose it. They read the codes and some of them include P0137, P0157, P0175 and P0172. Do you have any idea what might be wrong with my car?

A: The P0137/P0157 codes indicate the "re...

The P0137/P0157 codes indicate the "rear" (behind the catalytic converters) oxygen sensors are not functioning properly. In turn, they are signaling (incorrectly) for more fuel, which is causing the P0172/P0175 over-rich codes. This is clogging your converters, as well as causing poor performance. Both rear oxygen sensors should be replaced. A YourMechanic professional can come to your home or office to replace your vehicles oxygen sensors.

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