Not passing SMOG

Troubleshooting
1

Hello all my name is:Lex
For my: 1994 3000GT VR-4

So the car passes everything while on high RPM, but on idle it is Rich.
Before throwing parts in random I just wanted to consult you guys on what I should focus on>

  1. Mass Air Flow sensor: Is there a difference between Turbo and DOHC NA version?
  2. Idle Air Control Valve: Might be stuck in a position that limits air on idle?

Any ideas that I haven’t thought of are also welcome.

2

There are a number of different maf sensors used. Do you have any smoke or error codes?

3

Hello, Joe.
OBD1 so no check engine light and no codes.
There is no smoke on idle either.

4

This is a hard one since there are no error codes, what scan tool are you using?

5

Running rich at idle? fuel injector cleaning and re-calibration

7

Fuel injection cleaning is step 3 if ICV (step 1) and MAF (step 2) do not yield desired results.
Thank you for your suggestion.

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