* Major Battery Problem: A completely dead or severely degraded battery is the most likely culprit. A dead battery won't supply enough power to the gauges, causing them to read low or zero. The rough running engine could be due to insufficient power to the ignition system, fuel pump, or electronic control modules (ECMs).
* Alternator Failure: A failed alternator won't recharge the battery. If the battery was already somewhat weak, this would quickly drain it completely, leading to the same low gauge readings and rough running engine as a dead battery.
* Broken or Loose Battery Cables: Poor connections at the battery terminals can prevent sufficient power from reaching the electrical system. This could manifest as low gauge readings and inconsistent engine performance.
* Wiring Problems: A significant short circuit or break in the main power feed to the electrical system could cause low gauge readings and erratic engine behavior. This could impact everything from the ignition system to the fuel injection system.
* Faulty Voltage Regulator: While part of the alternator system, a failed voltage regulator can cause erratic voltage output leading to issues similar to a completely failed alternator.
Important Note: A severely rough-running engine combined with low gauges indicates a serious problem that could lead to further damage if not addressed immediately. Do not attempt to drive the vehicle in this condition. Have it towed to a qualified mechanic for diagnosis and repair. Continuing to run the engine could cause irreparable damage to various components.
