Ok I know the title says it all...oh know not another one of these. I am a new member to the forum but I have been search everyone's post for about 3 weeks now trying to figure out my problem. With no luck thus far here goes the thread.
The actual symptoms are that at idle is idling really rough almost like loping. It tries to die then comes back. It will do this in Park, Reverse, nuetral, or Drive only at stop. When driving the car runs great. good acceleration. But when I come to a stop light and just let it idle it messes up. I have noticed though that when it is idling rough if I turn on the AC the rpm's change and it quits temporarily.
Ok so I am driving a 2001 Focus Se. 2.0 SOHC. I have installed a Cold Air Intake (Short Ram) on it. I have taken it apart multiple time and made sure the was no leaks. I keep getting this code from the CEL with an OBD-II reader. (PO171) I know, System Fuel to Lean Bank 1. I have had the intake on it for more than 3 months prior to it acting this way.
What I have done so far is change the fuel filter, changed the Spark Plugs, Changed the O2 Sensor before the Cat. Tried different grades of fuel and fuel treatments. I have cleaned the MAF 3 times in the last week with CRC MAF cleaner.
My next steps are checking the fuel pressure at Idle. Does anyone know what the pressure is supposed to be at idle? Also does anyone else have any thoughts of what it could be? I am thinking that it could be a bad MAF, EGR Valve, IACV, or bad fuel Pump. Any help would be greatly appreciated. Thanks