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Q: How much is a tune-up for a 2000 Lexus RX300, with 249k mileage?

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Check engine light on. Autozone gave me the following codes when I stopped by to check the cause of the check engine light:

P1349 Variable Valve Timing System (bank 1) P1349 " P0300 Random Misfire detected P0301 Cylinder 1 Misfire detected P0303 Cylinder 3 Misfire detected P0305 Cylinder 5 Misfire Detected P1130 A/F Sensor Circuit Range/Performance

My car has 249000 miles.
My car has an automatic transmission.

Is a tune up the answer to the problem, or I need more than that?

While you may be due for a tune up, a general tune up (spark plugs, filters, etc) may not be the answer to all those faults. Random misfires across multiple cylinders can be due to poor fuel quality, poor fuel pressure, worn spark plugs, faulty ignition coils, engine wiring harness issues, or even due to the airflow sensor fault. If the engine control unit is getting incorrect readings - or no readings at all - from the mass airflow sensor, the air/fuel mixture can be off and cause misfires. The root cause(s) for the fault codes should be addressed before replacing anything else. Once the faults are corrected, then any maintenance items should be addressed.

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