If you decide to use these techniques on your ISM, then you accept total responsibility for the outcome. By doing this, it controls the idle at all temperatures. I know it is found on 240's and 740's from 84-88 and possibly earlier or later than that. 1987 and earlier cars had ISM's that were not especially durable. In 1988, they substantially improved the ISMs, so you should insure you purchase the new design if you need to buy a new one.
All ISMs are interchangeable for the years mentioned above.
Before you go out and buy a new one, try fixing the old one first. Here's how I did it on our 87 740. Whatever you do, do not use carb cleaner on the ISM unless you can insure it will not get into the electrical parts of the motor. Checking Out the ISM 1. The important things are that the readings be near the 18-20 Ohm range and that they be nearly the same for both readings.