Well this just happened about 2 hours ago well driving. My book says its p0430 three way catalytic converter system low efficiency (bank 2). What in the world does that really mean. Information for the truck: 1996 chevy Tahoe LT with 5.7l vortec and 4l60e tranny. 197,280 miles. Bone stock engine ran only highway miles until I got it at 193,500 miles since then mainly city miles. Recently the truck has been running rough, has poor acceleration/power and sounds like it it missing. Soon I'm replacing the plugs, wires, distributer cap, and fuel filter. Recently the truck had its rear main seal and oil pan gasket replaced. Currently running conventional oil with a Fram tough guard filter. Truck sat with no oil for almost three weeks well I was working on it then I had to have it towed to a shop who finished the work. This truck is my baby and I want it back to how it was when I bought it.