I threw this SES light yesterday out of nowhere. Started the car up after driving for about 30 miles, it had a low idle (which it usually does) and then the SES light came on. I have the AMS intake with K&N cone filter and AMS intake shield. I also have the AMS UICP and Buschur catback installed. I've had all of the AMS parts installed for about 5,000 miles, and the exhaust for 3-4,000 miles with no problems.

I understand this code designates that the A/F ratio is lean, but has anyone else thrown this code? I saw one other thread regarding it, but I haven't seen P0171B come up.

The car is home, and I'll check the MAF, vacuum lines, and intake/IC pipes after work.. Anyone have any other suggestions? Thanks.