Been there, done that on a Coleman when we first moved into our sticks and bricks here in Vegas. Spent over a month using one until our furniture arrived. Over a few days, ours would loose some air, so first, soapy bubble check your valve first. A little over pressure on it will help, if that doesn't work, take it outside, and water check it with a hose.
Stan, Shirley & 2 Schnauzers
Former 2014 Daybreak XD34 Owner
USAF, Retired, Life Member: NRA, DVA, VVA, VFW, VSPA