I've got a stock '84 that idles a rough and surges when I'm in the throttle. Don't believe it does at WOT. I've checked for vacuum leaks, rebuilt the TBI, had the TBIs balanced, new plugs, wires, cap, coil, egr is good, replaced o2 sensor, IACs appear to be working fine, no codes. Interestingly it idles fine in service mode, idling with pins A and B shorted. Any thoughts/input would be appreciated.