2017 LEXUS IS 300

Typical onset: 60,000-90,000 mi

Symptoms: Rough idle, especially when cold, Hesitation or stumble on acceleration, Misfires (P0300-P0306 codes), Loss of power and reduced fuel economy

Fix: Walnut-blasting the intake valves requires removing the intake manifold and blasting each port. Expect 4-6 hours labor. Some shops use chemical treatments first (less effective long-term). This is a maintenance item on all direct-injection engines, not a defect, but Lexus has no service interval for it.

Estimated cost: $600-1,200

Typical onset: 80,000-120,000 mi

Symptoms: Pink or milky transmission fluid (coolant contamination), Transmission slipping or delayed engagement, Check engine light with transmission codes, Overheating transmission temps on scan tool, Sudden transmission failure if cooler ruptures internally

Fix: The external transmission oil cooler (part of the radiator assembly on some variants, or separate unit) can fail internally, allowing coolant and ATF to mix. Once contaminated, the 8-speed automatic is toast—requires full transmission replacement or rebuild plus cooling system flush. If caught early (fluid discoloration only), flushing and cooler replacement may save it. Replacement trans: 8-12 hours labor.

Estimated cost: $4,500-7,500

Typical onset: 70,000-110,000 mi

Symptoms: Clunk or thud when shifting from park to drive/reverse, Vibration felt through cabin at idle in gear, Excessive driveline movement during hard acceleration, Visible cracking or separation in rubber mount

Fix: The rear transmission mount (and sometimes front engine mounts) wear out from the torque of the V6. Straightforward replacement, 1.5-2.5 hours labor depending on which mounts need doing. Use OEM or quality aftermarket—cheap mounts fail quickly.

Estimated cost: $300-600

Typical onset: 90,000-130,000 mi

Symptoms: Hard starting or extended cranking, Rough running and misfires under load, Fuel trim codes (P0171/P0174 lean codes), Loss of power on highway pulls

Fix: Direct-injection fuel systems are sensitive to fuel quality. Clogged fuel filter (in-tank, not serviceable separately on some models) or dirty injectors can cause driveability issues. Injector cleaning/replacement: 3-5 hours labor for all six. If in-tank pump module replacement needed, add another 2-3 hours. Always use top-tier fuel to prevent this.

Estimated cost: $800-2,000

Typical onset: 100,000+ mi

Symptoms: Rattling noise on cold start for 2-5 seconds, Check engine light with VVT codes (P0010, P0011, P0020, P0021), Rough idle or reduced power if actuator fails completely

Fix: The 2GR-FSE's VVT-i (variable valve timing) actuators can develop internal wear, causing startup rattle or performance loss. Replacing cam actuators requires valve cover removal; 4-6 hours labor for both banks. Not a frequent failure on this engine, but worth inspecting if rattle persists beyond 10 seconds after cold start.

Estimated cost: $1,200-2,200

Typical onset: 90,000-140,000 mi

Symptoms: Coolant leak from front of engine, Whining or grinding noise from accessory belt area, Overheating or high coolant temp reading, Visible coolant weepage around pump housing

Fix: The water pump is buried behind the timing cover and driven by the timing chain. Failure means a major teardown: front engine disassembly, timing cover removal, 8-12 hours labor. Always replace the thermostat and do a coolant flush at the same time. Some techs recommend doing this preemptively at 100k if no service history exists.

Estimated cost: $2,000-3,500