So my “service engine soon” light just came on. First time ever. I’ve had the car 8 years and I’ve had ETS intake and ETS EXHAUST on the car for 7 of those 8. I just checked the code with my access port and it’s say it’s this P0171 Fuel system lean Bank 1. Literally first time the light has ever come on so is the sensor going bad or dirty ? Recommendations ??

 

Going to add to the discussions here. '10 Ralliart here, had an AMS intake on it from almost new. In the past 2 months I've also gotten this 0171 code, both times were when I started the car (so never during driving). Checked all the piping, but no idea what could cause this error and why it pops up now. After 5 start cycles the CEL light turns off and everything's back to normal. Car runs as it always has, so no probs driving.

 

I am getting the same code after 2 month of me installing MAP intake and uicp. Only other mod possibly pertaining to the p0171 (unlikely because it is after the cat) is my invidia q300 catback. Code sets at idle and while driving.

-I’ve cleaned the maf sensor
-I’ve done a smoke test to check for vacuum leaks
-I bought a new maf sensor just to check for a possible faulty sensor. (My stock sensor only reading 2.55 g/s).
-I’ve checked the o2 sensor (not replaced). Numbers fluctuate normal