Whats Up, I Just Swapped A 98 Gsr Into My 2001 Ls. Everything Is All Gravy Except For A Damn Code 21, And An Irratic Idle. It Hops From 1000 Rpms Up To About 1500 R's. I Am Running An Obd 1 P72 Chipped Ecu, With An Obd2b To Obd 1 Conversion Harness. Right Now Everything Is Still Pretty Much Stock. I Want To Get It Running Awesome Before I Make It Go Faster. Any Help Would Be Greatly Appriciated.