I have a 2004 Expedition with the 4.6. The engine has 220,000 miles on it. In the spring it would take 2 tries to start it. This didn't happen everytime but often. I took it to the shop to have the spark plugs changed, coils checked and injectors cleaned. The shop said all those items were in good shape but the intake plenum needed cleaning. They cleaned the intake plenum and the truck started great for about 6 months. Now it's having the hard start issue again. I took it back to the shop and this time they did a pressure test on the fuel pump. Fuel pump makes pressure and holds it. They can't find anything wrong. They didn't have the hard start issue while it was there. So we still have the problem, still not every time we start the truck but often. Yesterday it took 3 tries to crank. Now I noticed the fuel level was low. I filled it up last night and so far it has started 1st try.

I think that the issue happens when the fuel level is low and the truck has been sitting for more than an hour but I'm not 100% sure this is the only time it's hard to start

Any ideas as to the cause?