Code PO171 : System too lean (bank 1)
Description : The adaptive fuel Strategy continuously monitors fuel delivery hardware. The test fails when the adaptive fuel tables reach a rich calibrated limit.
You may have a vacuum leak, stuck IAC Valve or dirty MAF. You may find that if you remove the internal Sensor from the MAF Case that some debree has collected on the thin wire. If you find debree, use a Q-Tip to clean it. DO NOT USE CHEMICALS TO CLEAN IT. If no debree is found, try a Known Good MAF Sensor. Still no fix, move on to testing for a vacuum leak. ( listen for a whistle noise or spray some starting fluid around the intake area while the engine is running). The IAC Valve (Idle air control) may be stuck , remove it and clean the carbon and reinstall if no vacuum leaks are found. Feel free to check out some of the other resources on the website as there may be some helpful information available.