With the used Edelbrock 600-cfm carb (part number 1406) on the truck who knows what the previous owner did to it and what the jets inside actually were. All we know is that with the new O2 sensor reader we could now see what the engine demand for fuel was. We let the engine warm up to operating temp and noticed the idle and cruise were on the lean side – 16:1 air/fuel ratio. Wide-open throttle was close, but I only wanted to address one thing at a time. Time to open this Edelbrock 600-cfm carb up.