: 96 STS P0171 & P0174 Code

06-07-10, 09:16 PM
I can't figure out why I keep getting the lean bank codes on my 96 STS Northstar engine. I seemed to start after replacing the MAF sensor and cleaning the throttle body. I have since replace the spark plugs, PCV valve & fuel filter. I've checked for vacuum leaks and haven't found any.

06-08-10, 01:14 AM
Check your intake duct clamps.

06-08-10, 10:46 AM
did you put in a new maf or used maf? sometimes the simple stuff like tightening clamps is not enough. you may need to have the car scoped to determine if all sensors are performing as expected. i have been screwing around with my 96 for years and have been getting many o2 codes lately. i have yet to take it to a shop since it is my occasional driver. if it throws a code i just live with it.

06-08-10, 05:52 PM
Yes I have checked the duct clamps and the MAF sensor is new. Does anyone know if there is anything that I could check in conjunction with the Idle Air Valve? I pulled it and cleaned the valve and seat. Could a bad O2 sensor cause this? I'm almost to the point of taking to a shop to have a scope put on it. Thanks for the tips.

06-08-10, 09:34 PM
Did your car's built-in Diagnostic Trouble Code reader/scanner give you any current fuel/air codes ??