Cylinder 4 Injector Restricted
The P02A8 code indicates that the engine control module (ECM) has detected a restriction in the fuel injector for cylinder 4. This means the injector is not delivering the proper amount of fuel, often due to clogging from debris, carbon buildup, or fuel deposits. The ECM monitors fuel trim and injector flow rates; when cylinder 4 deviates significantly, it sets this code. This can lead to misfires, poor performance, and increased emissions.
01. Most Common Causes
- Clogged fuel injector due to carbon or debris
- Contaminated fuel
- Faulty fuel injector electrical connector
- Low fuel pressure or failing fuel pump
02. Symptoms You Will Notice
- Engine misfire on cylinder 4
- Rough idle or hesitation during acceleration
- Check Engine Light illuminated
- Decreased fuel economy
03. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Perform a fuel injector balance test to compare cylinder 4 flow.
Step 3: Inspect injector electrical connector for corrosion or damage.
Step 4: Check fuel pressure and fuel quality.
Step 5: If restricted, remove injector and clean or replace it.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as the restriction can cause misfires, catalytic converter damage, and reduced engine performance. Short trips to a repair shop are acceptable.
How much does it cost to fix?▼
Cleaning the injector may cost $50-$100, while replacement can range from $100-$300 per injector plus labor. Diagnosis fees are typically $50-$150.