It sounds as if the engine is running too lean. There are several ways to richen the overall fuel mixture. I have seen people monkey with the EHA's, I have seen them richen them up with the mixture screw and I have even seen them wire in resistors on the coolant temp sensor. Let your local tech take a crack at it. Your O2 sensor could be telling one thing and the engine actually be doing another if the sensor is faulty.
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