P0305 on a Lexus: Causes, Fixes & Repair Cost

🟠 Moderate severity · drivable

If the check engine light is flashing, stop driving — a severe misfire can damage the catalytic converter. A steady light is usually safe for a short drive to a shop.

What P0305 means on a Lexus

On a Lexus, P0305 means the engine computer detected a misfire on cylinder 5. Lexus V6 and V8 models have six or eight cylinders, and cylinder 5 is on the bank opposite cylinder 1. Because the code names one cylinder, the cause is usually its spark plug, ignition coil, or injector.

Is P0305 common on Lexuss?

P0305 appears on Lexus V6 and V8 models like the ES, RX, GS, and GX, usually at higher mileage. Worn spark plugs are the most common cause, and Toyota-built engines generally have reliable coils, but they can fail with age. Clogged or leaking injectors are less common.

Commonly reported on: ES, RX, GS, GX.

Symptoms

Check engine light on (flashing if severe)
Rough idle or shaking
Loss of power or hesitation
Poor fuel economy

Common causes

most common: Worn or fouled spark plug on cylinder 5
common: Failing ignition coil on cylinder 5
less common: Clogged or leaking fuel injector
less common: Wiring or connector issue at the coil
less common: Low compression from engine wear

How to fix it

Fix	DIY?	Typical cost
Replace the spark plug on cylinder 5 (or all plugs)	Yes	$50–200
Replace the ignition coil on cylinder 5	Yes	$90–280
Replace or clean the cylinder 5 injector	Mechanic	$250–600
Run a compression test if the misfire returns	Mechanic	$100–200

Frequently asked questions

Which Lexus models have a cylinder 5?

V6 and V8 models like the ES, RX, GS, and GX. Four-cylinder models set P0301–P0304 instead.

Is P0305 common on a Lexus?

It's less common than on some brands because Lexus ignition parts are reliable, but plugs wear out like any other car. A worn plug is the usual reason at higher mileage.

Can I keep driving my Lexus with P0305?

A steady light is usually fine for short trips. A flashing light means a severe misfire, so stop and have it towed.