Quite a bit of your information is factually incorrect. Here are the facts:
1) VLO has earned over the past 4 quarters: 1.82+1.18+.85+.57=4.42/share.
2) There weren't any "obvious items" that came out of those numbers. Those were simply the company's EPS. Valero didn't report "adjusted EPS" like some companies do.
3) Assuming 4th quarter earnings of 1.70/share (average of the range they provided today), the trailing 4 quarters' earnings are 4.30/share. Thats a P/E ratio of 12, not 17-18 as you stated
4) Valero last traded around $28/share on Nov 2, 2012. It has generally moved higher since then. That was 2 days after Valero reported a drop in earnings for 3Q2012, and a loss on their Ethanol segment (which has since returned to profitability.) That was also before Valero unlocked value by spinning off CST Brands. Interesting that as of Nov 2, 2012, the trailing 4 quarters' EPS at that time was only 2.04. So the argument that the stock price has doubled while earnings has dropped is factually incorrect because earnings have actually more than doubled.
I wouldn't be shorting this now. If anything, Valero has more room to run.