Mechanical Issues:
* Binding Cable: The most common culprit. The accelerator cable can become frayed, kinked, stuck in its housing, or bind due to corrosion or debris. This is often exacerbated by age and the cable's natural wear. Inspect the cable for any visible damage, stiffness, or binding points along its length, from the pedal to the throttle body.
* Return Spring Failure: The spring that pulls the accelerator pedal back to its idle position might be broken or weakened. This allows the pedal to remain depressed even after you release it. Check the spring's integrity visually.
* Debris in the Pedal Assembly: Dirt, debris, or even a small object can become lodged around the pedal pivot point, preventing it from returning freely. A thorough cleaning of this area might resolve the issue.
* Worn Pedal Pivot: Over time, the pedal's pivot point can wear down, leading to increased friction and a sticky feel.
Vacuum Related Issues (Less Likely, but Possible):
* Vacuum Leak: While less directly related to the pedal itself, a significant vacuum leak in the intake system *could* affect throttle response, making it feel like the pedal is stuck. This would be accompanied by other symptoms, like poor idle or rough running.
Throttle Body Issues (Less Likely, but Possible):
* Sticking Throttle Plate: Though less common, the throttle plate within the throttle body could become sticky due to deposits of carbon buildup. This would cause the engine to continue revving even if the pedal is released. Cleaning the throttle body is a potential solution.
Less Likely, but Important to Consider:
* Electronic Throttle Control (ETC) Issues (unlikely for a '88): 1988 300ZXs likely don't have electronic throttle control. If your model *does* have ETC, then malfunctioning sensors or the ETC module itself would be potential causes (though less common on older cars).
Troubleshooting Steps:
1. Visual Inspection: Start by carefully examining the accelerator cable and pedal assembly. Look for obvious signs of damage, binding, or debris.
2. Cable Movement Test: Gently try moving the accelerator cable by hand. It should move smoothly and easily return to its original position. If it's stiff or binds, the cable needs attention.
3. Clean the Pedal Assembly: Carefully clean any dirt or debris around the pedal pivot point and cable housing. Use compressed air or a brush.
4. Check the Return Spring: Inspect the return spring for breakage or weakness.
5. Check the Throttle Body: If other issues are ruled out, you might need to check for a sticky throttle plate or perform a throttle body cleaning.
Important Note: If you're not comfortable working on your car's mechanical systems, it's best to have a qualified mechanic diagnose and repair the problem. A stuck accelerator pedal is a serious safety concern.
