I think Bruce is right. It usually takes up to 5 seconds or more at times, but if you get it lit, rotate the knob and flame all the way down, then slowly back up before releasing it, that sometimes will help. It's remotely possible your ignition probe is out of alignment or something, but doubtful. If your pressure wasn't up to snuff, it probably wouldn't burn well or stay lit very long after you did get it going, and your refridgerator might not ignite or run well on gas. But regulators can and do go belly up.
Joel