OT: L-Jet help for an Italian sports car Options

[Cevan]

I’m helping a buddy sort out an issue he’s having with a ‘80s L-Jet water-cooled car. This is a car he’s just about done restoring. This is the problem: The car does not idle at a constant speed. Once warmed up, the idle rises from 1000 to 1900 rpms over the course of about 1 ½ to 2 seconds and then drops back down to 1000 rpms in about ½ second. It appears to rev freely.

We have checked all the L-Jet components per his shop manual: AFM, dual relay, TPS, AAR, cold start injector, temp sensors, etc. O2 sensor replaced. We have double checked for vacuum leaks. We have also taken the AAR and cold start injector out of the loop. We’ve confirmed all the injectors are firing and that the cold start injector doesn’t leak.

Any ideas? Could it be a defective or malfunctioning dizzy? How does one go about cleaning it, assuming it's sticking inside?

Thanks.