I was disconnecting connectors on my scrap Nx2000 to find out which ones it really needed to start.
I also had a dying idle, so my opinion is it could be anything, but I must say no MAF and no TPS connected and the car wouldn't even idle for more then 5 sec and with MAF and TPS, it was ok enough 'to drive home'. However it wasn't warmed up yet and openeing throttle made a hwwuwm-mwfbrlllmmrehhbbpm blop blop p pp ppp pblop and engine dies.
Putting all connectors back made it idle at 850 again and cold or warm. I can't tell for sure but I'd say vacuum was and still is ok.
No error codes?