iacv can be taken off and cleaned out with some evaporative cleaner.
TPS- Just replace it. its a cheap way to rule that out (maybe even fix it).
you can pressurize the system by going into boost...hence the *PSI.
easiest way to see if you have a boost leak...go around all the couplers and fittings with Throttle body cleaner...and spray it...if the engine changes RPM rapidly...you found it. Check the charge pipe...right off the turbo. You can also use that TB cleaner on the IACV cleaning.
TIP: If you disconnect the IACV and its acting the same...you know thats not it.

thanks for searching first, i know it doesn't always yield answers.