code #33

[s13rb25det]

hey, I started my car this afternoon to go home from work and it started doing a really weird thing. when I am cruising at a solid speed it starts speeding up with out me pressing on the gas also when I am at a stop and then take off it will bog down a little bit. it kind of reminds me of when my knock sensor went out but I have replaced that just under 2 years ago. so I got home and I checked for codes and got a #33 which is a 02 sensor I have replaced the o2 sensor very recently also and from what I have been told is when you get a 02 code it is mostly a leaky injector I dont know if this is true or not but I know my injectors are not leaking I did a leak down test on the a few months ago and replace one of the about a year ago. it was very hot out today and I wonder if that is what caused this problem? has any one here ever had this concern and what was the fix? oh yeah I checked timg and it is dead on at 20btdc and I am running 89 octane.