Rich Fuel mix with High Idle

["Rustproof" <Rustproof@xxxx>]

I am having some trouble locating the cause of a high idle condition (2000 rpm) and an extremely rich fuel mixture. The mixture is so rich that the catalytic converter will begin to glow. I have checked the ECU and O2 sensor with an o-scope and find that the signal and duty cycle are within normal operating parameters. The frequency valve seems to be operating normaly as well. All of the extra adjustment screws are seated to allow for the ECU to do its job. The Idle control air valve seems to be operating OK and is not sticking. No leaks at the cold start valve. The idle switch is is OK too. The fuel injectors are all operating with a good spray pattern and have been checked for equal fuel distribution. I am running out of ideas. Has anyone run into this sort of thing before? Thanks in advance for any suggestions you guys may have.....
Rustproof
Vin #1559


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