[EC900]

What’s the rpm on warm idle?
950 is the normal range, little more is expected dead cold start, but should settle at 950. Dropping to 600/700 rpm caused my 2.7 to stall at the traffic light. Fixing a few vacuum leaks caused the idle problems in my case.
Another suspicion might be an injector(s) and also, did anyone tamper with the mixture settings?
Any lean/rich or exhaust smoke? Try to inspect the plugs to get a rough idea to the mixture setting.

Here’s some things I experienced:
On the mechanical side, idle can be interfered by worn bushing in the pedal cluster causing the throttle rod and clutch rod hitting one another and binding up when the nylon bush broke apart from the bell crank assembly. Easy fix btw. Inspect by removing floorboard, right of the accelerator. There’s also another bell crank assembly to the throttle that could also have a worn bushing, this could make adjusted idle speeds to be inaccurate.