I've had some problems with grounding the blue-white wire in the past also. On some occasions, grounding did nothing; on others, it stalled the engine.

In your case, logic would say it's the Air Control Valve not functioning correctly. Grounding the wire is supposed to close it, so you can adjust the throttle bypass air with the valve out of the equation. If bypassing the valve doesn't change anything, one would think the valve, the control signal to it, or simply the blue-white wire to the ECU is the issue.

For one of the problems I had (I frankly forget whether it was the "no reaction" or the "stall"), cleaning the throttle body fixed my problem. I just used a spray can of throttle body cleaner at the throttle opening, with the main air hose from the AMM removed. I paid particular attention to the passageway for idle air, that the idle adjust screw connects to. I noted how many turns from fully in the screw was, then attempted to remove it so I could blast some cleaner in. It didn't seem to want to come out, so I abandoned this, and simply blasted into the passageway just inside the throttle opening. (Apparently you should avoid getting cleaner into the throttle endstop switch; it can damage it).

After doing all this, the new setting for the idle adjust screw was drastically different - I believe it was now further in (logic would dictate this). Grounding the wire then gave the expected result. I'm thinking now that it's more likely this fixed the "stall" problem, however, I don't think there's a downside for you trying this simple fix. Otherwise, I would think you're back to the valve or its control signal.

*** check the current posting "O2 sensor voltage check"; there's a great test submitted by Fitz Fitzgerald on how to test the Air Control Valve.