Hey guys so I have experienced a P0171 code for years. It comes and goes as it pleases. Over time I have replaced many part's and tried many possible fixes (Both o2 sensors, pcv valve, gas cap, cleaned the MAF sensor, fuel injector cleaner, etc. Also replaced the rusted out Fuel fill neck which kept the code away for a solid 5 months. My real reason for this post is because I have noticed Engine shaking/vibration at Idle. Now this only happens once the engine is warm. So if my engine is Misfiring once warm could it be related to the P0171 lean condition?Also important to note I never seem to get any Misfire code. I have never replaced Spark plugs either...