If you have not already done so I would try a new CTS anyway.
RR should have been able to diagnose this, ideal place to do it.
Also it it has not been done in the last two years do the fuel filter.
I had a problem where mine(2wd) would produce no power until boost, then bang all of a sudden, that did NOT show as lean on the RR but massive problem on the road, new filter cured it though.
Can't see the TPS causing a massive problem like you have, partially blocked filter will though, goes when on boost as fuel pressure raises and CO richens.
It should be perfectly happy at your CO setting
tabetha