2001 Ford Escape Rough Idle Cold Start

2001 Ford Escape Rough Idle @ Cold Start
V6 with 130k miles, starting the engine below 35 degrees F will promptly start, idle rough & stall if you don’t manually maintain an idle of 1,000 rpm’s or more for about 4 minutes to which the engine coolant temperature is reading normal operating temperature, at this time the engine will still not idle automatically and will stall. The engine sounds like it’s missing on one or more cylinders. The good news is, turn off the engine – let it sit for 5 to 10 minutes, start it and the engine will perform like new for the rest of the day – the forgoing is very consistent & if you don’t mind the wait, the car is very dependable.


Replacement Parts History, the idle problem started last spring – changed out the Idle Air Control (IAC) Valve, 5 minute job – no improvement, a few weeks later the weather warmed up and the car ran great for the next 7 months until the temperature dropped.


The OBD II scan tool, reported PO174, PO171, P1151 & P1131- system too lean Bank 1 & 2, Lack of HO2S11 & HO2S21 switches / sensors. I replaced all 4 Oxygen sensors / no improvement. The following parts were replaced based on 130k miles, ease of installation & cost, Throttle Position Sensor, Front 3 Spark Plugs, PVC, Mass Air Flow Sensor, Engine Coolant Temperature Sensor, Test gas pressure at Injectors, Replaced 6 Fuel Injectors, 3 Rear Spark Plugs, Ignition Coils & upper intake manifold gaskets,
EGR System Sensor & Regulator, Camshaft Position Sensor, checked connection of the Power Control Module. Replacement parts were individually installed and relearned through the PCM before taking another step. All the parts installed easily (15 minutes or so) with the Fuel Injectors, Plugs & Ignition Coils taking the most time of about 2 hours and replacements recommended with 130k + miles. This process has been fun, a joke & interesting learning about “Emissions Control Systems” fortunately the car gets me where I need to go and warm weather is on the way.


Theory – a component outside the coolant system connected to the engine block or within the engine compartment, when warmed restores operation. Remember the engine still will not idle with the coolant up to operating temperature, it must transfer the heat somewhere, because when you start the engine 10 minutes later the coolant has dropped temperature but the engine will perform like new. I welcome any thoughts and or suggestions, Thanks for your time. Joe W. Dearborn Mich.
Joe; Did some searching through TSBs. Found a couple; Check for fuel pressure regulator leakage, air leak after MAF, and smoke test for vacuum leaks. In addition, there was one for PCM reprogramming for cold idle quality problems if built before 03/01.