Toyota Repair: 22Re stumble/Fuel problem?, vacuum hose, toyota truck

Question
My Toyota truck 1986 started to miss and stumble like it is dropping a cyl.New motor good compression good spark. Plugs #1,2,3 looks the same #4 plug looks different like it is not getting fuel at times.I took the vacuum hose to the return regulator and found a ball bearing in it shutting off the vacuum but the truck ran fine with it that way for the last eight years I owned it. I thought it was the motor as it had 300 thousand miles on it but iy is doing the same with the new motor. Will appreciate any comment. Pump or injector or what? Thanks.......

Answer
Whatever the cause is it is isolated to the #4 cylinder, I kind of lean towards an injector problem, with the engine running you should be able to feel the injector clicking open and closed or you can check them with a piece of rubber hose held to the injectors and listening for the click noise, the #4 injector should click like the others but the problem is that even if it does it could still mean that it's clogged or restriced.