Yea, I know that was you Alfa_Chan. Before you told me about it, I hadn't thought about it. We'll . . . . I just "assumed" . . . . and you know what that means. Anyway, "throttle cable" is now an early step in my SPICA troubleshooting guide.
Sniady - There is no choke on an SPICA system. I think what you're refering to is the pull cable on the lower left rear of the center console. That's a "hand throttle." All it does is pull the throttle cable back a little so you can set a throttle position without pressing on the accelerator. It's ONLY function is to help keep the rpms up a little when the engine is cold and warming up. It is NOT a cruise control and should NEVER be used while the car is in motion. It DOES NOT release when you press the brake pedal like cruise control systems do.
To check to be sure it's not restricting the foot throttle, look where the cable goes through the firewall (center left side of the firewall, then goes through a loop on a tang attached to the throttle actuating bar (that's pivoted on the firewall). With the hand throttle pushed all the way in, it should be loose on the throttle bar and not preventing the manifold butterflys from going to full shut (engine hot). Since you say you've already checked the throttle cable (there should be just a bit of slack allowing the throttle bellcrank to go against the throttle stop screw), then the hand throttle is probably not set too tight either.
I think you're down to a grossly maladjusted idle stop screw (unlikely, but possible) or a bad T/A.
In a SPICA system, the Thermostatic Acutator acts as a choke would in a carb engine. However, it does NOT restrict airflow in the intake like a carb, but rather mechanically enriches the mixture as well as opens the throttle slightly to provide a higher cold idle. As the engine heats up, the TA piston retracts and the FI pump throttle arm returns to the reference position (.019" clearance). This also closes the throttle butterflys back to full closed so the ONLY air the engine is getting is through the idle system (small hose from air cleaner to manifold, then the 4 even smaller hoses to each cylinder barrel).
Do not go and start "adjusting" anything like idle stop screws, etc. What we're doing right now is just checking the operational integrity of the most likely suspects in your high idle problem.
If the TA checks out good, then a complete reset and tune of the SPICA system is probably in order. That's going to require a lot of reading and understanding and a nice Saturday afternoon . . . no beer until job is finished.