I was coming back from running my car at the track tonight when it started to act a little weird on the highway, if I let off the gas it would stutter briefly. I got to a stoplight and the idle was going all over the place, from 500 rpm to 1300 rpm, fluctuating rapidly in between those. The car also stuttered badly upon leaving the light. I took it back into my parking garage and let it idle for a little while and the problem seemed to go away. I left it off for about half an hour, went back down and drove it again and there were no problems this time. Anyone else experience this?

 

Your computer might have been adjusting your idle trim (like when the battery is disconnected)... I've had mine do the same after driving it hard. Just play with her a little and she'll figure out what's going on.

...I think.

 

Update...I found that my K&N filter was barely on after checking everything. That seemed to be the problem as I've had no irregular behavior after tightening it. You guys don't think I damaged the engine at all? It seems to be running fine.