Chart 8

Lack/Loss of Power

NOTE: Verify symptom is reported under normal driving conditions without excessive engine/vehicle load. Also, be aware of the engine rpm/speed limiting functions of the PCM.

NOTE: For applications with knock sensor, a lack of power may result when the vehicle is operated with a breakout box installed at the PCM. The KS circuits are not shielded in the breakout box, and KS signal noise may be noticed by the PCM. If this happens, spark timing will be retarded and a lack of power may result.

SYSTEM/COMPONENT	REFERENCE ( PINPOINT TEST - CNG, FLEX-FUEL & GASOLINE ) unless noted
Automatic Transmission Fluid Throttle Linkage Air cleaner element	Visual
Check the Following PIDS: DPFEGR (if equipped) (hot idle value within 0.15V of KOEO value) LONGFT1 / LONGFT2 (value between -20 and +20) For 4.6L E/F Series: IMTVF with both Key On Engine Off, and with transmission in PARK/NEUTRAL and engine rpm greater than 3000 rpm (PID should indicate no fault (or NO) in both situations).	DPFEGR PID value not within 0.15V of KOEO value: For vehicles equipped with ESM EGR: GO to H: Exhaust Gas Recirculation System Module (ESM) STEP HH34. All others: GO to E: Exhaust Gas Recirculation (EGR) Systems STEP HE57. 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. IMTVF PID indicates a fault: GO to U: Intake Air Systems STEP HU42.
Fuel Delivery System	Natural Gas Applications: GO to B: Natural Gas Fuel Delivery System STEP HB1. All Others: GO to C: Fuel Delivery System STEP HC1.
Secondary Ignition	For vehicles equipped with a coil pack ignition system, GO to PINPOINT TEST JC . For all others, GO to PINPOINT TEST JB .
Mass Air Flow (MAF) Sensor	GO to C: Mass Air Flow Sensor STEP DC25.
Exhaust System	GO to F: Catalyst Efficiency Monitor and Exhaust Systems STEP HF5.
Base Engine	Engine System - Refer to the appropriate ENGINE article.
Automatic Transmission	Automatic Transaxle/Transmission - Refer to the appropriate AUTOMATIC TRANSMISSION article (Diagnosis by Symptom - Poor Performance).
Brake System (brake drag or binding)	Refer to the appropriate BRAKE SYSTEM - GENERAL INFORMATION article.
Mustang only: Check for lack of A/C cutoff under wide open throttle conditions.	Audible (listen for A/C clutch to disengage during a brief wide open throttle, then re-engage a few seconds after returning to idle). Follow Symptom CHART 21 if A/C does not cutoff.
Supercharged applications: Supercharger bypass system	GO to J: Supercharger Bypass Control STEP KJ13.
5.4L SC F -Series: Check high speed fuel pump secondary circuits	GO to A: Fuel Pump Relay STEP KA52.
Additional Testing	GO to Z: Intermittent STEP Z1.
Additional Checks: NOTE: Some applications have a PID that will indicate whether the PCM is reducing torque (095E b0), and if so, why the torque is being reduced (095E b1-13). Customer driving habits Correct PCM vehicle identification (VID) block information (refer to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY - FLASH EEPROM . IMRC linkage (if equipped) Clutch (M/T) Charging System Engine RPM/speed limiting functions of the PCM (look for incorrect high vehicle speed signal from ABS, VSS or OSS)	Visual. Appropriate service information article.