A while ago I threw a code for the rear 02 sensor being stuck open or not responding. I replaced that o2 sensor with a new one thinking that would solve my problem. I thought I had it fixed but now it seems like if I go over 65 mph it throws the same code. Anybody have any ideas what could be causing this? It runs fine as long as it is under 65 but as soon as I get over it throws the code and stays on. Thanks