1990 302 EFI
Is there a trick way to replace one injector without taking off all the upper stuff and the fuel rail? This injector is on the drivers side, and is accesable. I was wondering if I can kind of pop the fuel rail off one or two injectors and gently move things over so the faulty injector can be taken out/put in.

I'm hoping some smart person has figured out how to do it.

 

the only way that injector will come off is by taking the fuel rail. i dont know about the upper manifold part, but even on mustangs, where my exp is, you need to take the upper off to get access

 

The injectors are under a hard metal line that is bolted by tabs to the intake manifold. Some of which you can't get at without removing the upper plenum.
These bolt may even be froze in.
If that happenes then heat the heads with a torch to a red color then let them cool. This should break the bond with the alum from expansion then cooling.
Both ends of the injector have 'o' ring seals as well as an electrical connector.
Use some lube on the rings to put the injectors back into the holes and into the hard line.
Sorry there is no short cuts.

 

I just got done replacing all eight on my 1990 F-150 5.0 EFI. And yes you could do the drivers side. you need to take the bolts out and then you get the ones you need out on the drivers side. But forget any short cuts on the passenger side. Just don't yard up on the line pull up enough just to get them in and out, you will be fine.