One more thing, Jump terminals A and B on the aldl just like you are trying to read codes. But this time start and drive the truck, you will notice the CEL flashing fast, this indicates that you are operating in open loop, i.e. no feedback from 02 sensor. when the truck starts running like ****, look at the CEL to see if it is blinking slower, this indicates closed loop operation, i.e. feedback from 02. Try to see if the driveability issues coincide with the change from open to closed loop. Of course, do this test from a dead cold motor. This ability is called field diagnostic mode and is an often overlooked feature on these trucks.