To diagnose the problem, we need to know *what* exactly is wrong with the accelerator. Is it:
* Not responding at all? This points to a serious problem – likely electrical or within the throttle body itself.
* Sluggish or jerky? This could indicate issues with the throttle position sensor, cables (if cable-operated), or the throttle body.
* Sticking? This might be due to a sticky cable, a problem with the pedal assembly, or debris in the throttle body.
* Giving erratic responses? This often points towards a faulty throttle position sensor or a problem in the electronic control system.
Possible Causes and Troubleshooting (Do NOT attempt repairs without proper knowledge and tools):
* Throttle Cable (if applicable): Older Transits might have a throttle cable. Check for fraying, breakage, binding, or kinks. Lubrication might help a slightly sticky cable, but replacement is often necessary if it's significantly damaged.
* Throttle Position Sensor (TPS): This sensor tells the engine control unit (ECU) the position of the throttle plate. A faulty TPS can lead to poor performance, stalling, or check engine lights. Diagnosis requires a multimeter or an OBD-II scanner to check sensor voltage. Replacement is often the solution.
* Throttle Body: The throttle body controls airflow to the engine. It can become dirty or sticky, leading to poor response. Cleaning the throttle body is possible with specific cleaner, but it requires careful attention. A damaged throttle body will need replacement.
* Accelerator Pedal Assembly: Problems here are less common but can lead to sticking or unresponsive pedals. Inspection is necessary; replacement may be required.
* Electronic Control Module (PCM/ECU): Problems with the ECU are rare but can cause severe accelerator issues. Diagnosing ECU problems usually requires specialized tools and knowledge.
* Vacuum Leaks: A vacuum leak in the intake system can affect engine performance and throttle response. This requires a thorough inspection of all vacuum lines and connections.
* Wiring and Connectors: Check for any damaged or corroded wiring related to the accelerator system, TPS, or throttle body.
What to do:
1. Safety First: If the accelerator is malfunctioning, don't drive the vehicle. It's a safety hazard.
2. Check Engine Light: Is the check engine light on? If so, have it scanned with an OBD-II code reader to get diagnostic trouble codes (DTCs). These codes will pinpoint the likely cause.
3. Visual Inspection: Check the obvious – cables, pedal assembly, etc., looking for visible damage.
4. Professional Help: Take your Transit to a qualified mechanic. They have the diagnostic tools and expertise to accurately identify and safely repair the problem. Attempting complex repairs without the proper knowledge can be extremely dangerous and expensive in the long run.
In summary: Don't try to fix this yourself unless you are a trained mechanic with the appropriate tools and safety equipment. The accelerator system is critical for safe operation, so professional help is recommended.
