Vibration?

[mr.sinical]

Waz up guys? This vibration has been getting worse over the past several months. Usually at low RPM's under a load. Got an automatic, fairly new fuel pump. Usually right when it shifts into 4th gear. Sometimes when I take off in 1st too. I changed the U joints - they were factory (235,000. miles) but they were not dry or bad. I think I might have a bad injector or two. Sometimes, during the vibration, it feels like a cylinder misses and the truck jerks. But it doesn't do this at high RPM's. It pulls like a champ. I had a bully dog chip that was giving me a couple of problems - I am now rumming an evolution chip. Any thoughts?

[1997_F250]

You can pull your valve covers and see if the injectors are all squirting oil when the truck is running. If they aren't squirting oil, you can check to see if the screw under the solenoid is tight and also check the clearance. I forget what the clearance should be set at, but I want to say .004 is good and .002 is on the lower limit.