Drewry929

My wife and I have had our LS400 for about a month now, and decided to take it to our first ever autocross event. Well, half way through the second lap, the powering steering went out and I limped back to the paddock. At idle and low speeds, the car groans when turning the wheel. Even turning the wheel, while stopped, just a couple degrees and holding it causes a groan, as if the PS is trying to help.
This marks the third time the PS has gone out, the first two were when I drove it 8 hours home from picking it up. I let it sit for awhile the first two times (over night, and around 2 hours) and it started working again. This time, not so much luck.
Any thoughts on what happened and if the autocross could've caused it? Maybe some air in the system? I plan on doing a flush ASAP, and hopefully that will fix it, but do you guys have any other experience or ideas?