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Home >> Ford >> 2000 >> Contour SE, 2.0 3, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 757 (Engine Controls - Symptom Charts - Bi-Fuel CNG) >> Step 3: No DTC(s) Present Symptom Chart >> Chart 7

Chart 7

WARNING: This page is about a different car, the 2004 Ford Pickup Heritage. However, it is still accessible from the selected car via links, so may be relevant.

Unique Idle Concerns

Additional Driveability Concerns

NOTE: If vehicle runs normally after the ignition key is turned OFF, check for damaged ignition switch, IGN RUN circuit short to power or VPWR circuit short to power. Refer to the appropriate service information article and the appropriate SYSTEM WIRING DIAGRAMS article.
SYSTEM/COMPONENT REFERENCE (PINPOINT TEST - BI-FUEL CNG unless noted)
Base engine air leaks, including proper sealing of intake manifold and components attached to intake air (such as the EGR valve or IAC valve). Refer to appropriate ENGINE article.
Intake Air System (air leaks) Refer to INTRODUCTION - CNG, FLEX-FUEL & GASOLINE .
Cooling System Refer to the appropriate ENGINE COOLING article.
Air Conditioning System Refer to the appropriate CLIMATE CONTROL SYSTEM article.
Fast idle concerns: 
Key on, engine off, monitor the PCM TP MODE PID while wiggling TP sensor circuits. TP MODE PID can also be monitored during vehicle drive. With throttle closed, TP MODE PID must be C/T (closed throttle).
TP Mode PID is not C/T with throttle closed: 
Monitor the PCM PIDs TP V and TPREL for sudden changes while checking for intermittent TP circuit/connector concerns. Also check for loose/worn throttle plates. If no concern is found, go to INTRODUCTION - CNG, FLEX-FUEL & GASOLINE .
NOTE: At vehicle start, the TPREL will begin at about 1.25 volts, and count down to the lowest TP V value seen since engine start. If the TP V value goes below the normal range, then increases again, TPREL will set to the lower voltage. If TP V is about 0.04 volts greater than the TPREL value at closed throttle, the PCM will go into part throttle mode.