Is that too much to hope for?

I'm getting a new truck. Its a used 2007 Nissan Titan. The dealership has it priced at 15998$, with 51,000 miles, V8, 2WD, loaed features, blah blah blah. 15K is almost perfect to get the amount I want for a monthly payment, no matter what finance rate I get. I know everyone tries to haggle for a better price, but I suck at it. But I think 998$ I can manage. Is that too much to ask the dealer to take off?