couldnt you take out the injectors and dip them in some thing like a parts cleaner

 

Go to Ford Fuel Injection and buy their Injector rebuild kit. There is a small screen basket in the top of the injector that get clogged up with junk and they will need to be replaced. The website even has a DIY instructin fro the injectors. NO Injecter cleaner will not solve this problem. They will need to be rebuilt. Its not hard to do

BigLar

 

I would check u joints and the carrier bearing, they have a tendency to shudder at higher speeds when they start to wear out. I remember growing up my parents bronco had the e4od tranny that went out and every time it shifted to high gear it would vibrate like crazy. If this tranny has never been rebuilt, the clutches are pretty weak in that transmission and will go out in less than 100,000 miles and a complete rebuild should cure it forever. The rebuild kits come with much stronger clutches