John,
I assume you've done and re-done (because it's an art not a science) the linkage tour that Joe has put on the site. With that ticked off, you may have a vacuum leak (brakes, etc), but it more simply it may be a case of needing to adjust the setting of the FI pump idle, using the small screw at the back of the pump. When I re-fitted my FI pump after some modifications, I found it had been leaned out (at my request). The car was running lean at idle and hunted. It took quite a bit of adjusting the idle screw on the pump and the idle screw at the butterfly to get the correct combination.
I'd suggest the lean running test, the procedure for which is on the site. It maybe that you're running lean and so a click or two of the idle screw may sort the problem. After a bit of faffing, my car idles perfectly at around 800rpm.
I'd suggest you start there.