Okay I have not yet chipped my car, so I haven't personally experienced how alot of you guys are experiencing "sluggish" performance after chipping your car on some days but good performance on others. My only thought is that these cars all come with that "intelligent driver input" feature that is supposed to sense how you are driving and "adjust" the behavoir of the car accordingly. Could this feature be the cause of some days your cars acting "sluggish" and other days performing well? I could see that if a couple of days your are mostly driving (safely, legally, and slower) so your car would sense this and adjust to save on gas mileage. But other days you are driving (fast, racing from red light to red light, and driving over the speed limit consuming more gas) so your cars are sensing this and adjusting the engine to compensate. WHO KNOWS I COULD BE WRONG!!!!!! BUT, this is why I think some of you who have chipped your cars are experiencing these problems. The reason why I think this is because my "unchipped" car does the same thing. One day it seems a little sluggish when it shifts and acceleration is slower, but other days it seems that I have tuned the crap out of the engine and I accelerate extremely well. Just a thought.