Intake Backfire (popping from the engine bay): This usually indicates a problem with the fuel/air mixture being too rich or ignition timing being too advanced. Possible causes:
* Vacuum Leaks: A significant vacuum leak can disrupt the air/fuel mixture, leading to a rich mixture and backfires. Check all vacuum lines for cracks, disconnections, or loose fittings. Pay close attention to the lines connected to the intake manifold and the brake booster.
* Faulty Mass Air Flow (MAF) Sensor: The MAF sensor measures the amount of air entering the engine. A faulty sensor can send incorrect readings, resulting in an incorrect fuel mixture.
* Dirty or Faulty Throttle Position Sensor (TPS): Similar to the MAF sensor, a malfunctioning TPS provides incorrect information about the throttle position, affecting the fuel delivery.
* Fuel Injector Problems: A clogged or leaking fuel injector can cause a rich fuel mixture.
* Incorrect Ignition Timing: While less common in a 1995 Tahoe, if the ignition timing is too advanced, the fuel/air mixture may ignite prematurely, causing a backfire. This usually requires specialized tools to diagnose.
* Crank Position Sensor (CPS): If the CPS is malfunctioning, the engine's timing may be off, leading to backfires.
Exhaust Backfire (bang from the tailpipe): This typically suggests an issue with the exhaust system or ignition system. Potential causes:
* Exhaust Restriction: A severely clogged catalytic converter, muffler, or other part of the exhaust system can cause exhaust backpressure to build up, leading to backfires.
* Ignition System Problems: Worn spark plugs, faulty spark plug wires, a failing distributor cap or rotor (if equipped), or a weak ignition coil can cause misfires that result in backfires.
* Valve Problems: Burnt or sticking valves can also contribute to exhaust backfires.
Troubleshooting Steps:
1. Start with the Easy Stuff: Check for obvious things like loose vacuum lines, visibly damaged spark plug wires, and worn spark plugs.
2. Visual Inspection: Examine the entire exhaust system for leaks, blockages, or damage.
3. Listen Carefully: Note when the backfiring occurs (during acceleration, deceleration, idle, etc.). This can help pinpoint the cause.
4. Check Engine Light: If the Check Engine Light is on, have the codes read at an auto parts store or using a code reader. This can provide valuable clues.
5. Professional Diagnosis: If you're not comfortable working on your car's systems, take it to a qualified mechanic. They have the tools and experience to diagnose and repair the problem accurately.
Without knowing the specifics of *when* your Tahoe backfires (under what conditions), it's impossible to give a definitive answer. Provide more details, and I can offer more specific guidance.
