Some 2006-2010 Lexus IS250 vehicles may exhibit one or more of the following conditions:
- MIL on, with DTC P0300, P0301, P0302, P0303, P0304, P0305 and/or P0306.
- Rough running after coming to a stop with the engine at normal operating temperature.
- Engine runs rough with misfires present after a cold soak startup.
Perform a misfire diagnosis. If the concern is not resolved after following the repair manual misfire diagnosis, proceed with the following repair procedure.
1. Run the engine to operating temperature.
2. Remove the intake air surge tank assembly.
3. Remove all ignition coils and spark plugs.
4. Remove the starter relay.
5. Using a funnel, pour 1.0 ounce of GM Upper Engine and Fuel Injector Cleaner (GM P/N 88861802) into each of the six cylinders via the spark plug holes.
6. Place and secure shop towels over all spark plug tubes.
7. Crank the engine for five seconds using a jumper wire at the starter relay terminals 3 and 5.
8. Let the engine soak for 60 minutes.
9. Spray a generic lubricant into each bore.
10. Rotate the crankshaft pulley clockwise two full rotations by hand to disperse the bore lubricant.
11. Crank the engine for five seconds to redistribute the top engine cleaner.
12. Allow one additional hour of soak time prior to starting the engine. Proceed with reassembly during the remainder of the soak period.
13. Remove any remaining top engine cleaner from the combustion chambers and spark plug holes.
14. Reinstall the spark plugs and ignition coils.
15. Reinstall the intake air surge tank assembly.
16. Drain and refill the engine oil.
17. Start the engine and immediately test drive the vehicle for a minimum of 15 minutes. Use the lower gears and moderate throttle to operate the engine at an increased rpm. It is normal for smoke to be emitted from the exhaust during the first few minutes.
18. Change the engine oil again, along with a new oil filter.
19. Using TIS Techstream, clear any DTCs that may have been set.
20. Confirm normal vehicle operation.
