Changed Air Filter now it wont run properly

[bahamasvitz]

Its a 2000 Vitz, 2 Dr Auto, AWD.
I changed the Air Filter, removing all the air filter tubes etc to clean the same time, made sure they were all dry before putting it back together. The sensor was removed as well and put back on good. It all seems like it is back together as it was.

Problem I have is right after all of that, i turn it on and when you throttle it, there is no response for a few seconds then there is a sort of hanging bogging response, do it again, same thing. I checked the battery and cleaned the negative terminals, all good, voltages check out okay on load also. I had the dealer change an O2 sensor a couple days ago which check engine light still keeps coming on, but at least I wasnt having this problem Im having now.

Is there anything noticeable that I might have knocked loose down in there, or not put back on properly, to be causing this kind of delayed throttle? It started to get dark which made things worse and Ill have to check it in the morning, but since I cant find a manual for this vehicle, im looking for some ideas even if they are only general mechanic stuff. Ive had this delayed response on it before, but thats just when it is cold.

Thanks,
Rory