4.3 has idle issue. rough idle/shake in gear. First symptoms were only when a/c on. Now most of the time, but much worse with a/c on. Load from steering pump has no effect on idle. Always starts and drives fine, runs best cold after sitting all nite with a/c off.Once a/c is turned on it will idle poorly for rest of day, a/c on or off and mileage can drop as low as 8 to 10 mpg in traffic. New plugs-wires-cap-rotor IAC valve, MAF,map, tps engine temp and o2 sensors Recent fuel pump and pressurized fuel system cleaning.HELP?