[cmiovino]

One thing I've seen with the Cobb OTS map on my WRX is at idle, I have positive LTFTs at idle constantly. They'll vary up to about 12-13%, but are always at least 7%+. I've had the car smoke tested for vacuum/boost leaks, new front O2 sensor, new MAF sensor, car drives fine, etc.

The thing is, at idle, the percentage difference the ECU needs to add or remove is larger than when the car is moving and there's airflow through the intake at even 2k RPM. Generally speaking, seeing higher LTFTs are idle isn't super terrible, however a tune or tune revision (if you've already had it professionally tuned) can adjust fueling at idle to fix this. Just make sure all everything is 100% mechanically sound from a leak perspective - you obviously wouldn't want to tune around a clear leak somewhere when you should really fix it.

Cliff notes: It's probably fine and you don't need to super worry about it at idle. If it does max out and the ECU can't add anymore, it'll throw a code and it'll be at idle. Your fueling is likely ok in as you give it any throttle or load - concentrate on those numbers more. A professional tune can fix it if it's on OTS tune, or the tuner needs to spend more time adjusting fueling at idle if it's already protuned.