P0266Fuel & Air

Cylinder 2 Contribution/Balance Fault

P0266 means the PCM detected cylinder 2 is not contributing its expected share of power, based on crankshaft speed variation. It points to a weak injector, low compression, or a mechanical issue on that cylinder.

🚗 Limited. A cylinder not contributing evenly causes rough running and can lead to misfires and converter damage over time.

MEDIUM

severity

🎯 Top Causes, Ranked by Likelihood

#1Weak or clogged injector (cylinder 2)$150-$400

35%

A restricted injector under-fuels the cylinder.

#2Low compression on cylinder 2$500-$3000

25%

Worn rings or a valve issue reduces the cylinder's output.

#3Injector wiring or connector fault$100-$250

20%

Intermittent contact reduces injector performance.

#4Vacuum or intake leak at cylinder 2$100-$400

20%

An unmetered air leak upsets the cylinder's mixture.

🩺 Common Symptoms

Rough idle
Cylinder 2 misfire
Check engine light
Loss of power
Uneven running

💰 Repair Cost: DIY vs Shop

DIY Cost

$100-$400

Shop Cost

$150-$3000

📋 Free OBD2 Code Cheat Sheet

The 50 most common codes with likely cause and DIY fix cost. Sent once, no spam.

🔧 How to Diagnose P0266

1Confirm cylinder 2 from freeze frame

2Run an injector balance and compression test

3Inspect the injector, wiring, and connector

4Check for vacuum leaks near cylinder 2

❓ Frequently Asked Questions

What does P0266 mean?

Cylinder 2 is producing less power than the others based on crankshaft speed, usually from a weak injector or low compression.

Can I drive with P0266?

Only briefly. A weak cylinder causes rough running and can develop into misfires that damage the converter.

How much to fix P0266?

A cleaning or injector is $150-$400. If compression is low, repairs can run $500-$3000.

🔗 Related Codes

P0263P0269P0202P0264P0265