Chart 1

WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2010 Mercury Milan, 2010 Mercury Mariner, 2010 Mercury Grand Marquis, 2010 Lincoln Town Car, and 2010 Lincoln Navigator L. However, it is still accessible from the selected car via links, so may be relevant.

Stalls/Quits: Idle, Acceleration, Cruise, Stall After Start
Runs Rough
Misses
Buck/Jerk
Hesitation/Stumble
Surge
Unique Idle Concerns: Rolling Idle

NOTE: For some vehicle applications, the engine may stall if left running while refueling. Advise the customer to turn the engine off while refueling to avoid contamination or damage to the evaporative emission (EVAP) system.

BUCK/JERK SYMPTOM CHART

SYSTEM/COMPONENT	REFERENCE (article 5 Pinpoint Test unless noted)
Check the following parameter identifiers (PIDs): DPFEGR (if equipped) (hot idle value within 0.15 volt of the ignition ON, engine OFF value) LONGFT1/LONGFT2 (value between -20 and +20%) VPWR (value between 10.5 and 17.0 volts, and within 0.5 volt of battery voltage)	DPFEGR PID value not within 0.15 volt of ignition ON, engine OFF value: For vehicles equipped with an exhaust gas recirculation system module (ESM), GO to PINPOINT TEST H . For all others, GO to PINPOINT TEST HE . LONGFT1/LONGFT2 value low (-): Continue diagnosis. Concentrate checks in areas that would cause the engine to run rich. LONGFT1/LONGFT2 value high (+): Continue diagnosis. Concentrate checks in areas that would cause the engine to run lean. VPWR not between 10.5 and 17.0 volts: REFER to the appropriate Charging System article and carry out the Inspection and Verification to continue diagnosis . VPWR between 10.5 and 17.0 volts, but not within 0.5 volt of battery voltage: CHECK the B+ voltage to the powertrain control module (PCM) power relay. CHECK the VPWR circuit between the PCM and the PCM power relay. CHECK the PWR GND circuits.
For vehicles that run rough at idle: Check the INJx_F PIDs (the "x" indicates the injector number) with the ignition ON, engine running. There is 1 INJx_F PID for each engine cylinder. All INJx_F PIDs must indicate no fault (or NO).	The INJx_F PID(s) indicate a fault (an injector circuit concern is indicated). For Flex GTDI, MKS 3.5L, MKT 3.5L and Taurus GTDI vehicles, GO to PINPOINT TEST DI . For all others, GO to PINPOINT TEST KG .
Mass Air Flow (MAF) Sensor	GO to PINPOINT TEST DC .
Manifold Absolute Pressure (MAP) Sensor (Flex GTDI, MKS 3.5L, MKT 3.5L and Taurus GTDI)	GO to PINPOINT TEST DN .
Secondary Ignition System	For vehicles equipped with a coil pack ignition system, GO to PINPOINT TEST JC . For all others, GO to PINPOINT TEST JB .
Fuel Delivery System	GO to PINPOINT TEST HC .
Exhaust System	GO to PINPOINT TEST HF .
Positive Crankcase Ventilation (PCV) System	GO to PINPOINT TEST HG .
EVAP System	GO to PINPOINT TEST HX .
Charging System	Visual. REFER to the appropriate Charging System article and carry out the Inspection and Verification to continue diagnosis.
Universal Heated Oxygen Sensor (HO2S) (Escape 3.0L, E-Series 4.6L, E-Series 5.4L, Expedition, Fusion 3.0L, F-150, Flex, Mariner 3.0L, Milan 3.0L, MKS, MKT, Navigator, and Taurus)	GO to PINPOINT TEST DZ .
Automatic Transmission	REFER to the appropriate Automatic Transmission/Transaxle article, Diagnosis By Symptom to continue diagnosis.
Base Engine	REFER to the appropriate Engine System article and carry out the Inspection and Verification to continue diagnosis.
Intake Air System	GO to PINPOINT TEST HU .
Additional Testing	GO to PINPOINT TEST Z .
Additional Checks: Some vehicles have a TQ_CNTRL PID available. Check this PID to determine if the PCM is reducing torque, and if so, why the torque is being reduced. As a PID display example; 0 equals no torque reduction requested, 1 equals torque truncation, which cuts fuel to protect when line pressure falls to minimum limit and 2 equals traction control event, which cuts fuel/spark for traction control. Correct PCM vehicle identification (VID) block information. Refer to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) to carry out the Making Changes to the VID Block procedure. Be aware of engine RPM/speed limiting functions of the PCM (look for incorrect high vehicle speed signal from ABS, VSS, or OSS). Verify the fuel filler cap is correctly tightened or the capless fuel tank filler pipe is correctly sealed and not physically damaged. Drivelines Manual transmission/clutch Charging system Traction control system (if equipped) A/C system (for surge with A/C on) Speed control system (for surge with speed control on)	REFER to the appropriate article.