Well, this isn't my specialty, but since your post has been here so long, I'll give it a try.
When you drive a fuel injected car at partial throttle in the range you mentioned, it tries to use the oxygen sensor to to lean out the mixture for optimum economy. When you give it more than 2/3s throttle, it goes strictly by the fuel map in the computer and doesn't try to lean it out. In this situation, the engine runs quite a bit richer. Your engine miss is probably either a misfire or detonation. Lean mixtures detonate and misfire easier that rich ones. So, I would look at either your oxygen sensor or your knock sensor. A bad knock sensor would let the computer advance the spark too far and create detonation which would be less pronounced with 92 octane gas. So my first choice would be the knock sensor. However, it's probably easier to change the oxygen sensor, and it's more common to have problems with the oxygen sensor, so I would start there. Your car will probably run better with a new oxygen sensor, anyway.
Dr. Loot's Assistant
Monday, August 3rd, 2009 AT 9:58 AM