I think that you have no choice, at this point, but to change the secondary. To simply guess that it is OK when you have a fuel delivery problem is not acceptable. 10 minutes and $10. rules it out.

I had the SDL missing on the highway, like a gas engine. Most thought it was the tank filter. Well, I was not about to change the tank filter unless I was at the end of my options. Primary and secondary and the problem was eliminated.