The most likely cause of a fuel leak at the throttle body on this engine is a faulty fuel pressure regulator (FPR). The FPR is often integrated into the fuel rail, and a diaphragm failure within it can allow fuel to leak into the intake manifold via a vacuum line connected to the FPR. This is not a simple DIY repair for most people.
Here's a breakdown of what's involved, and why it's generally best left to a professional mechanic:
Possible Causes (Beyond the FPR):
* Fuel Injector O-Rings: While less common to leak *at* the throttle body, a failing injector o-ring can cause fuel to leak into the intake manifold, eventually showing up near the throttle body.
* Throttle Body Gasket: A severely damaged or improperly installed throttle body gasket could allow fuel to leak past. This is less likely if the leak is significant.
* Fuel Rail Leaks: Cracks or loose connections in the fuel rail itself can lead to fuel spraying.
Why it's difficult and potentially dangerous:
* Fuel System Pressure: Working on a fuel system requires careful attention to safety. Fuel under pressure can cause serious injury. You need to relieve system pressure before attempting any repairs.
* Specialized Tools: You'll likely need fuel line disconnect tools, fuel pressure gauge, and potentially other specialized tools to properly diagnose and repair the issue.
* Safety Precautions: Working with fuel requires proper ventilation, eye protection, and fire safety precautions. Fuel vapors are highly flammable and explosive.
* Finding the Leak: Pinpointing the exact source of the leak can be challenging.
Repair Process (General Outline - DO NOT ATTEMPT WITHOUT EXPERIENCE):
1. Disconnect the Battery: This is crucial to prevent sparks.
2. Relieve Fuel Pressure: Consult your repair manual for the specific procedure for relieving fuel pressure in your 1997 Cavalier 2.2. This usually involves cycling the ignition switch.
3. Inspect the Fuel Rail and FPR: Carefully examine the fuel rail for cracks, leaks, or loose connections. Pay close attention to the FPR itself.
4. Test Fuel Pressure (if possible): A fuel pressure gauge is necessary to determine if fuel pressure is within specifications.
5. Replace the FPR (most likely): If the FPR is suspected, it needs to be replaced. This requires disconnecting fuel lines, potentially removing the fuel rail, and installing a new FPR.
6. Inspect Injectors and O-rings (if necessary): If the FPR is not the culprit, inspect the fuel injectors and their o-rings for damage.
7. Check Throttle Body Gasket (if necessary): Inspect the gasket for damage and replace if necessary. Ensure proper installation.
8. Reassemble and Test: After making repairs, reconnect the fuel lines, reconnect the battery, and carefully test for leaks.
Recommendation:
Because of the potential dangers involved and the complexity of the repair, it is strongly recommended that you take your 1997 Cavalier 2.2 to a qualified mechanic for repair. A fuel leak is a serious safety hazard that shouldn't be taken lightly. The cost of professional repair is far less than the potential cost of a fire or injury.
