Engine Performance problem
2001 Ford Taurus 6 cyl Front Wheel Drive Automatic 156000 miles
My 2001 ford taurus sel (duratech engine, 24v, V6) has 156,000 kms on it. It has recently started to idle rough when at a stop. It takes about 4 or 5 seconds to finally drop to approx. 500 rpms at which point it starts to " chug". It sometimes will speed up to about 700 rpms. It only stalls when the A/C is running in the same conditions. I recently had the fuel filter changed. The trouble codes that appear are P0171 and P0174 which are bank 1 and bank 2 running lean. It does sound like there is a vacuum leak but I can not find it. All of the hoses appear to be in good condition. I have read so many different things in regards to what it could be but haven't tried many of them (fuel filter replacement is the only thing). There is a check engine light that comes on. Through my research, Ive found out that the light is an emissions trouble light meaning it can be various different components.