Car won't turn over unless I press the gas

I went to start my car today and it wouldn't turn over. I then tried again, but this time pressing the gas and it turned over with no problems.

Any ideas on what may have happened? My car started just fine yesterday and I've never had this problem till today. My engine light is not on and has never came on since I've owned the car.

Could it be the spark plugs? I've been wanting to do a tune up but haven't had a chance.

2005 Acura TL 3.2L with Navi at 136,000 miles. Originally purchased at 102,000 miles.