I don't know the exact numbers of the air/fuel mixture, but he did tell me that he richened up the mix and it improved it somewhat, but not enough to get rid of it completely. The chip has been programmed a bit richer with a couple degrees of timing pulled out and it's tolerable for now, and I'm careful as to how I drive. I'm really stumped on this one too! It's got an occasional rough idle which makes me wonder if it's something else entirely. For now, i simply don't have the money to spend on it, and it definately runs better with the chip than without.. (tried it both ways back to back). Anyway, I'm gonna chill on it for now and just try to get over this wisdom tooth surgery!! Thanx to all for taking the time to reply!