* Catalytic Converter Failure: A clogged or failing catalytic converter can restrict exhaust flow, causing a loss of power, especially uphill. The burning smell is highly suggestive of this. A failing converter can overheat and potentially cause further damage.
* Ignition Coil or Coil Pack Problems: Multiple misfires indicate a potential problem with the ignition system. A faulty ignition coil (or a coil in a coil pack) can cause weak or intermittent sparks to one or more cylinders, leading to a misfire, loss of power, and potentially a burning smell from the excess fuel not combusting properly.
* Mass Airflow Sensor (MAF) Sensor Issue: A bad MAF sensor provides inaccurate readings of the air intake, leading to a lean or rich fuel mixture. This can cause misfires, loss of power, and potentially a burning smell.
* Fuel Pump or Fuel Filter: A failing fuel pump may not deliver enough fuel, especially under load (going uphill). A clogged fuel filter can also restrict fuel flow, causing similar symptoms. However, a fuel pump problem is less likely to immediately cause a burning smell.
* Intake Manifold Gasket Leak: A leak in the intake manifold gasket can cause a vacuum leak, affecting the air/fuel mixture and causing misfires, loss of power, and a possible burning smell.
* Oxygen Sensor (O2 Sensor) Malfunction: A faulty O2 sensor provides inaccurate feedback to the engine control module (ECM), affecting the air-fuel mixture. While it can cause misfires, a burning smell is less directly linked.
What to do next:
1. Retrieve Diagnostic Trouble Codes (DTCs): This is crucial. Use an OBD-II scanner to read the codes stored in the car's computer. These codes will provide valuable clues to pinpoint the problem. Auto parts stores often offer free code reading services.
2. Inspect the Catalytic Converter: Visually inspect the converter for any signs of damage, discoloration (extreme heat), or blockage. Be careful; it will be hot if the engine has recently run.
3. Check for Vacuum Leaks: Carefully inspect all vacuum hoses and connections for cracks or leaks.
4. Consider a professional diagnosis: Given the severity and multiple symptoms, taking your car to a qualified mechanic is highly recommended. They have the tools and expertise to diagnose the issue accurately and safely. They can test the components listed above and determine the root cause. Trying to troubleshoot this yourself without the proper tools and knowledge could lead to further damage or injury.
Ignoring the problem could lead to more serious and expensive repairs. Address this promptly.
