Every once in awhile since I installed the TVT-whatever kit (CAI, ported intake manifold and throttle body, bigger injectors) on Friday, September 24th, I've noticed that when I start the car, it initially idles around 1900 RPM which is much higher than normal. After driving it for a few minutes, the idle will drop back down to normal if I'm stopped at a stoplight but then if I'm waiting for any significant amount of time with the car out of gear (longer than 3-5 seconds), I notice that the RPM will creep back up from 800 RPM to 1800-1900 RPM and flutter back down to 1100-1200 RPM and then back up to 1800-1900 RPM again. I've noticed it'll do this randomly on my 25 mile commute but when I pull into the garage at home, it just idles normally again around 800 RPM.

Again, when I'm stopped at lights, with the clutch depressed and the transmission out of gear, my right foot is off the throttle completely and the engine will begin to idle higher than normal then drop back down to just above normal, again and again.

Does anyone have any suggestions as to what this might be? My immediate guess is that the stock ECU still trying to learn the fuel trim with the new injectors. I've not experienced any drivability issues or other problems since the install and no CELs have appeared on the dash, but I don't remember my XF idling strangely like this when it was bone stock.