It sounds like you have a massive intake leak unless I've misread your description. The BPV hose being off would account for this, although the intake or the inlet would also explain it. Check your plumbing for a leak. If the BPV hose is off, fix that and go from there.
You can reset the ECU by disconnecting the battery if need be.
Since you say you are unfamiliar with the fora I'll leave this thread here (it should be moved to general troubleshooting/maintenance) so you can see the response(s).