I put an O2 gauge in my car, the Sunpro they sell at Autozone and a Bosch O2 sensor. When the car is idling the sensor is reading a rich mixture one bar from all the way rich. When I rev the engine the gauge will go all the way to the lean bars. When I drive the car the gauge shows all the way lean. Is this normal? I have a 350 with an Edelbrock intake and a Holley street avenger 670. Any insight in this will be very appreciated. Matt

A properly setup carb will act this way. It will idle and accelerate at part throttle with the gauge reading near the ideal (usually yellow), at idle it may richen up slightly (top of the yellow or bottem of the green), at highway speeds mine would disappear lean. If I gave it a little gas and brought in the power tips on the primary metering rods (Edelbrock/Q-Jet) or opened the power-valve (Holley) it would richen up somewhat to the low end of the green. If I burried my foot into it, it would go full rich and stay. My TBI does essentially the same thing, but it hunts back and forth, rich to lean to rich in closed loop.

"Full rich" and "full lean" on a narrow band O2 mean virtually nothing. Without a wide band you have no idea what your mixture is save for whether it is above or below the narrow band's 14.73 ideal. Those gauges set up for the cheap narrow band O2s are worthless.

Ok thanks. The car runs great except for a slight stumble when I stomp it, I just didn't want to wreck a fresh motor by running in the lean side of the gauge.