Hey folk's im new here and im having some problems with this truck. It is only running on 1 thru 5 cylinders... number 6 you can pull the wire off and iti does nothing. has 140 pounds of compression and great spark. Has 48-50 pounds of fuel pressure i took alll the injectors out and cleaned them (nasty!) Tested them made sure the worked they did. Still the same thing. So checked power at the injector and with test light grounded, poke the red wire and its bright poke the other stil with the test light on the ground it flashes on all injector plugs. How are the injectirs getting a ground? Anybody?? Im confused! Im sure it has spark put plug on the block and turned it over and its firing. And vacum is steady on 20.

 

Broke valve spring maybe?

 

look up leakdown test.