b16 check eng lite on, stumbles on acceleration

my b16 runs great at idle now, everything is working order, but except for the check engine light comes on and my ECU is throwing code one (which i think is o2sensor) but my si ecu it blinked once too when i turned the key and ran it fine then. so maybe my vaccum lines are not hooked up right? theres still on on the intake mnaifold the is not plugged in but i didnt think it was needed, because i have no my vaccum lines to use. i dont know, anyone have an idea? help me out if you can please.

Hmmm... what ECU is it ? PR3, PWO ?

Error 1 Is O2 however it should not come on unt'il the car warms up.

Last time something like this happened to me was a MAP Problem.

if you could get a picture of your vacuum hoses that would help a lot.