I have a 2011 Lexus ISF. There are 2 defects in the car first the valley plate leaks because of incorrect sealant used at the factory. This issue was never recalled and only a few of original owners got it fixed by the dealer under warranty most of us have had to pay out of pocket with dealers charging up to $2000.
The second defect is on the right exhaust manifold it cracks at the number 4 cylinder. Then start sucking in air and you lose power at low RPMs. This too was never recalled as a defect.
I personally had to do both of them myself at a great cost and time. I hope you can get a ISF on the channel and bring it up. We were only about 5000 ISF imported to America but they went for upwards of $70,000.
The IS-F cars were decent cars but maintenance heavy and, as you found out, super expensive to repair when they broke.
