Did you ever solve your pilot problem? I have the same issue. Intermittently the pilot will not light even though there is ignition spark. Some times it lights immediately, some times it will spark for two or three minutes before it lights. some times it will spark for ten minutes until it goes into lock out. I have replaced the pilot safety switch and the gas valve.
Yeah, I just kept cleaning mine and eventually it worked. I'd replaced the aluminum tube last year because I damaged the old one getting it out. I think maybe there were just some specs of aluminum/dirt in the line from cutting it that just kept working themselves into the orifice. Why did you replace the gas valve?