I presume this worked out, as this was a couple of days ago.
As long as your driver is lapping at at least 3.55 in the dry, in the blue zone, you should have no problem, 3 laps down is certainly achieveable from 17 hours. I have done this with the same car, with no problem. The car which is likely to finish closest to you (due to them pitting every lap near the end), is the Audi R10, which doesn't suffer in the same way. The glitch is caused by the AI's drivers having no strength. Also, don't set a pit strategy for you driver, otherwise you will suffer from the same issue as your drivers become more tired. The magic number of laps is about 355.
Only once (from about 12-15 races) did I not observe the AI one-lap-pitting, and that was where almost the entire race was run in the wet, which resulted in slower laps, and longer stints meaning that they had longer to recover between getting into the car. For that race my driver finished 3rd, but could've easily won if coached. Additionally, if/when it rains, they will put racing hard tyres on the car after the rain, even if you started on racing softs. The better tyres to use are racing softs.
im afraid that he wont be able to make a come back 
