I have an 85 gt. When it idles it idles rough and when it warms up I have to keep my foot on the gas or it dies. It will restart without a problem but when on the road slowing down or shifting I have to throttle the gas. Any suggestions? Carb was serviced(not fully rebuilt), fuel tank cleaned new fuel filter and lines. new plugs, wires, distributor cap and rotary button, new wires, radiator flushed and filled. I don't know what else to do. It has a new wiring harness as well.