"I don't know what it was," he said. "Just a centre chest pain I had early in the race. It was really hard to breathe. Couldn't tell you what it was, I've never felt that before ... It was just hard to breathe. I had to take real short breaths. Felt like I was running a 400-mile marathon, which essentially I was. But I felt like I was running on my feet instead of in a race car."
Even so, it was clear that they would have to prise the steering wheel of the #18 out of Kyle's cold, dead hands before he was going to give up. And he wasn't about to hand the lead back to Greg Biffle anytime soon, either. The next round of pit stops commenced on lap 117 (the only drama being Brad Keselowski nearly skidding straight through his pit box) and once everyone had been through pit road it was still Kyle who led the field by some 1.2s over Biffle. He would eventually lead 59 of the 200 laps, but still not quite good enough to take the bonus for most laps led - that went to Biffle who had clocked up 68 laps in the lead in the first half of the race, but none in the second half.
All the signs were that this was coming down to a fuel conservation strategy battle, and the cars that were forced into the pits for fuel from lap 150 - kicked off by Jamie McMurray - weren't going to be able to make it the full remaining 50 laps to the end. Kasey Kahne stayed out until lap 155 but that proved to be a huge mistake, the #4 running completely dry and coughing to a dead stop in the pit box, which meant frantic efforts to feed in gas into the fuel lines to get the engine re-fired - a process that kept Kahne in pit lane for a torturous whole minute. His Red Bull team mate Brian Vickers was in next time around and narrowly escaped a similar fate.
It could have been worse. And for Juan Montoya it was, as he suddenly ran dry just as he passed the entry point for pit lane. The #42 abruptly slowed up, and then Andy Lally came screaming off turn 4 at race speed and simply wasn't expecting a slow car that high up on the track and ran straight into the back of him. Montoya was sent spinning through the grass (and, ironically, onto pit road after all) which Lally had a seriously crumpled front end and an engine that shouldn't be in that many pieces.
That brought out the fourth caution of the afternoon and interrupted the in-progress sequence of pit stops; Biffle had already been in but now got his lap back, while Kenseth had also been in and just managed to stay on the lead lap, and now took advantage of the opportunity that presented itself to come in for a quick top-up and emerge in the lead, with an eye to making it all the way to the finish in 40 laps' time in fuel conservation mode.
Matt Kenseth and Kyle Busch led the field to the green flag on lap 163 but it was Carl Edwards who got the best start and blew by both of them to take the lead, looking very strong indeed as did Denny Hamlin who slotted into second place ahead of Kenseth who had suffered some wheel spin at the get-go. But just about everyone was studying their fuel gauges very nervously - the leading pair figured they could just about make it all the way to the end, but most couldn't without a caution. And a green/white/chequered extended finish would screw up literally everyone.
Where was that vital caution? Kevin Harvick nearly caused it by getting up high and scraping along the wall in the final 20 laps, but NASCAR stubbornly refused to even twitch at bringing out a caution. Nor did they when Mark Martin drifted up high on the track toward the wall without realising that his Hendrick team mate Dale Earnhardt Jr. - who had already been into the wall earlier in the race and required some pit lane attention to sort out the damage - was working to recover his position and using the outside line to come past; Martin pinched him against the wall and Dale made contact with front right of the #88 against the concrete but was able to continue. Again it seemed that the caution had been avoided as there was no debris that required a yellow.
But that changed a few laps later: the impact against the wall had caused some bodywork damage to the #88 which in turn led to a cut right front tyre, and on lap 191 Dale was into the wall again - this time seriously enough to bring out the fifth and final caution of the afternoon.
Dale was furious with his team mate: "If the tables were turned, I'd have been smarter and given him plenty of room," said Dale. "He's older than me, been racing forever, he's forgot more stuff than I'll ever know. But still, I take better care of people [on the track] than that."
"It was an accident. We had an accident," said Martin, somewhat bemused by Dale's heat over the incident. "I had my front wheels cut and I let off the gas, and that's all I could do at that point ... It was my mistake."