Bad Fuel?

[JP2003]

2003 f-350 6.0 - Started running rough now wont start? Dont use the truck much, wife used it and brought it back with the fuel light on. So I had to stop at the sinclair station for fuel. Don't like to use their fuel but did'nt have a choice. Used it a few days later and it started with a rough idle and progressively got worse. I have drained the fuel put in new filters, tested the ficm(good) and put in new batteries. It will start if I spray either in it, which I don't know if thats ok to use? Fuel pump is working the top filter bowl fills up, and I have put fresh fuel in the bowl. I'm not sure if there is something else I can check, or do I have to throw in the towel and bring it to the shop? Thanks for any input/advice!!