Checks
| Action
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DEFINITION: The vehicle has a momentary lack of response when depressing the
accelerator pedal. The condition can occur at any vehicle speed. The condition is
usually most severe when attempting to make the vehicle move, as from a stop sign.
An extremely severe condition may cause the engine to stall.
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Preliminary Checks
| Refer to Important Preliminary Checks in
Symptoms - Engine Controls
.
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Fuel System Checks
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| | Inspect for low pressure during moderate or full throttle acceleration.
If the fuel pressure drops below specification, there is possibly a low or high
pressure regulator fault or a fuel system restriction. |
| • | Test for proper EVAP purge system operation. |
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Sensor Checks
|
| • | Test for proper TP sensor operation. A TP sensor that does not respond
quickly and accurately to throttle plate movement may cause this symptom. |
| • | Test for proper MAP sensor operation. A MAP sensor that does not respond
quickly and accurately to manifold pressure changes may cause this symptom. |
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Ignition System Checks
|
| | Important:: A higher secondary ignition voltage is required to operate the vehicle on
CNG than on gasoline.
|
| • | Test for proper secondary ignition system voltage output using only the
J 26792
Spark Tester. |
| • | Inspect for fouled spark plugs. |
| | If fouled spark plugs are
indicated the reason for the fouling must be found and corrected. |
| • | Test for faulty spark plug wires. |
| • | Test for an open ignition system ground -- if equipped. |
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Additional Checks
|
| • | Review service bulletins for module programming updates. |
| • | Inspect for manifold or air induction system leaks. |
| • | Test for proper generator operation. |
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