Engine Light

[Chevyman69]

Your truck has 4 O2 sensors on it, 2 forward and 2 aft of the cats. Now since you have gutted them it is screwing the computer around because the sole purpose of those 2 rear O2's is catalyst effeicency or that just means telling the computer the cats are working. They must recieve different signals or the SES light will trip. The fix, they are called O2 simulators, boxes that replace the rear O2's fooling the computer into thinking that the cats are still there and voila, no light. They can had at any performance or exhaust shop.