[yaz4real]

That high rpm indicates a very high vacuum loss. Are you sure all the vacuum connections are solid like the one connected to the brake booster on the firewall and pcv. I would start taking some of those main vacuum connections off and plugging with a golf tee or a pencil eraser as applicable to see if you get any variation. I would think a faulty TPS or IACV would give you a 2k high idle but 3k is uncontrolled. Again, no codes?

The IACV is a servo motor getting signal from the PCM to operate as such. It will stay in the last position as commanded by the PCM. I would tend to believe it is operating correctly based on the condition you report.

The spraying about the intake manifold when at high idle can indicate if a intake manifold gasket is at fault.

You are now at the point of beyond visual of vacuum hoses and its time to pull each completely, check and clean before reseating on both ends.