Dieseling/fast idle solenoid

[lippy]

My FE has a solid roller cam, and Brent recommends I keep the idle speed at 1200 RPM for proper lubrication of the valvetrain. If the car is set to idle at 1000 RPM or below it shuts off just fine, but above that I get some dieseling. I use the best gas I can find in CA.

The first thing I did to try to solve this problem was to change the bushing on the distributor (MSD) to the black one (18 degrees) and reset the total advance to 35-56. This gave me more initial advance and increased the idle speed, so I could then close the butterflies to achieve 1200 RPM idle. It didn't really help much.

Two people told me to install a fast idle solenoid to solve the problem. The solenoid is engaged when the ignition is on and holds the throttle open at the faster idle speed. When the ignition it shut the butterflies close fully. So I bought a Holley 46-74 and bracket and set it up, but it still diesels a bit (less than without), I think because the engine is still running pretty fast and doesn't have a chance to "pause" at a lower idle RPM before stopping, if that makes sense.

One solution I thought of is to wire a switch under the dash to the solenoid (next to my fuel pump cut off switch). That way, I can hit the switch to kill the solenoid before I shut the car, let it idle at 800 RPM or so for a second or two, and then just shut the car. I'm certain this will solve the problem, but obviously it's not ideal because it adds a manual step to the process.

Does anyone have a better way to solve this problem?