I have a 96 Cobra that isn't running right. When cruising along anywhere from 2-4k RPM's, you can floor it and it sputters really bad. I can drop a gear, floor it and it runs great. I can floor it from a stop and it runs fine. I've ran it at the local strip and it runs just fine there. Only problem is when calmly cruising around. I am throwing a CEL, but the only code I get is the rear o2 sensors (no cats). This has been going on now for a month or two. I always just thought I was in too high of a gear. I bought the car from my brother around April, he drove it last night and said that there was definitely something wrong, and it usually isn't like that. I've been running 91 or 93 octane gas (depending on where I fill up). Any suggestions on where to start? Thanks.