Here's why:
* Spark plug wires affect all cylinders: If your spark plug wires were bad, you'd likely experience misfiring and rough running in *all* gears, not just reverse.
* Reverse gear is mechanically different: Engaging reverse uses a different set of gears and linkages than forward gears. A problem within this system (like a faulty neutral safety switch, a problem with the reverse light switch, a low transmission fluid level, or a mechanical issue within the transmission itself) is far more likely to cause the engine to cut out only in reverse.
What to investigate first:
1. Neutral Safety Switch: This switch prevents the car from starting unless it's in Park or Neutral. A faulty switch might also prevent the engine from running in Reverse.
2. Transmission Fluid Level: Low transmission fluid can cause various problems, including shifting issues and stalling.
3. Reverse Light Switch: While seemingly unrelated, a problem with this switch can sometimes trigger other electrical issues, impacting the engine's operation.
4. Transmission Problems: More serious mechanical issues within the transmission itself are also possible.
5. Wiring harness issues near the transmission: Something might be rubbing or shorting in this area when reverse is engaged.
Addressing the spark plug wires:
While you should eventually check the condition of your spark plug wires (they should be inspected periodically anyway), it's a lower priority than investigating the reverse gear-specific issues listed above. If you have other symptoms of bad spark plug wires (misfiring in other gears, rough idling, etc.), then they should be addressed. But if the *only* symptom is stalling in reverse, focus on the transmission and related components first.
