Hard Start on 99 XLS 4.0 OHV

[lcplgolden]

-My explorer recently had coolant issues where there was a lot of back pressure and was overheating. Had a combustion leak test done, and it didn't detect head gasket leak. A mechanic buddy told me a clogged radiator after two days of messing with it. I replaced the radiator, and after burping it it runs at normal operating temp all the time, but I am losing up to 1/4 gallon coolant per week or so. And when I open radiator cap, even after not running it for hours, there is definitely still some back pressure, even though it's not overheating.
-Now, if I haven't ran it in a while and try to start it, it will turn over fine but will take several tries to start. Then it runs rough until I rev it up a little. But if it's still warm, it will start right up. New plugs and fuel filter. Fuel pressure gauge climbed to about 65psi on start up, and after shut off after 5-7 minutes it was at 35 psi which I told was normal. When I started it this morning, I turned key to on for one minute, pumped the accelerator, and then tried to start it. No change.
Could my coolant and hard start be related? Any help would be awesome

 

[T.C.]

Did you pressure test the system?

No signs of coolant anywhere?

 

[lcplgolden]

Not yet. Me and my buddy are going to this weekend. I had my upper intake manifold replaced about 6 months ago. I'm wondering if they reused the intake bolts instead of replacing them if that could be it because they are auto tensioning? Not really sure. But now there is kind of a knocking sound near somewhere near the accelerator it sounds like. Not sure if it coming from the engine or not, but my friend is going to check that out as well.