Im new here but Ive used seafoam for years. someone mentioned they don't know why people use it on the brake booster line? Well Im not sure on the Ranger exactly, im in process of buying one, on some cars the brake booster line is easier to access, and where the brake booster line is pulled from is on the top of the intake plenum, which will make sure your getting the seafoam spread through the intake and all cylinders.
What I usually do is put 1/2 a can seafoam into oil a few hundred miles before i need to change it.
Then when oil change time comes I slowly slowly suck the rest through the brake booster. turn off and let sit for 20 minutes. Start it up let it idle for 10 minutes, you can slightly tap the throttle a little bit. Then I go drive it until the smoke stops pooring out. Then come back change oil.
I don't use any in my tank, just high octane gas. Injectors for my car are very sensitive. This is all on my 92 Maxima SE tho. Like someone mentioned that some cars are different and you'll do it a bit different for each vehicle, but its basically the same idea