Hi guys,

This is just a general FYI if you ever encounter such problems. And before you comment, it has nothing to do with the GS300 Misfire Recall.

When any top-end work is performed on your DI engines which involves the removal of your fuel injectors, ALL of the seals must be replaced. The injectors are an interference fit in the block, and they are easily deformed upon removal (the seals are halfway between solid Teflon and rubber).

Although it is stated in the Service Manual that they are not to be re-used, this was overlooked on a couple of cylinders on my car.

The symptoms we got were P0300 and P030# (1,3,4 etc etc.) with NO associated codes for a damaged sensor or other error and rough idling (cold soak starts only). The give-away is that as the engine warmed up, the symptoms completely disappeared. The other give-away is that one cylinder would never register any misfire counts (and this injector was coincidentally brand-new).

We found this out from Lexus Corporate because it's only now that some of the engines are reaching certain mileages and having work like this performed.