bad vibration problems

Smoke or not has absolutely nothing to do with determining a bad injector. Look at it this way, if you have a dead miss from a failed injector, hot, or cold, load or bobtail and the engine doesn't smoke, does that mean all 6 injectors are fine? That sounds stupid right? The amount an injector has to work when pulling a loaded trailer, vs bob tail is night and day different. I have had trucks, N14 was the last one, where it ran great bob tail. You put a loaded trailer on it and under full torque it had a shake that was a cross between a dead miss and a ujoint falling out. That truck had good power, but the driver could tell it was missing some. Boost was still there as the rpm range it really acted up was narrow. #3 injector. I can't tell you specifically why. Maybe the solenoid wasn't strong enough to stay open longer. Maybe not enough fuel was flowing through it, who knows. I'm not saying you have an engine problem, but please talk to some more people who know more about engines. The guys you are talking to are giving you bad info! Engines will also run wierd like this when they are starving for power. Bad ecm power or dirty grounds can cause this sort of stuff too!

 

I agree with Heavyd on cleaning the and checking the ECM power and grounds, battery connections, grounds to the cab,and to the head. I have had units that have had fantom problems from stray voltage from the alternator. To test that turn on all the lights and accessories you can run the motor at 1200 RPM and check the voltage drop, from the alternator mounting to the right hand frame rail it there is above .4 volts I use to make up a cable, #4 is best but #8 will work.
Not every problem fits in an easy diagnostic trail, I like to do the cheap stuff first and a 4ft automotive battery cable, a tube of dielectric grease, with a bit of elbow grease, with a wire brush, will cure a multitude of problems.

 

as long as the dyno isn't at a cat shop. you will be alright doing that.

 

I dumped my air bags one night before I went to bed and forgot to air them back up the next morning before I pulled out. I had exactly what you are talking about. I thought my u joint had gone away. Could be if your bags are leaking down over night, they may not be airing back up like they should be. Something to liook into in the morning before you pull out check and see if they are tight.

 

I can't help but to believe you will be on the right track. Sometimes the most nerve racking symthoms can be a really simple fix.

 

my vibration ended when the shop putting in my clutch noticed my motor mounts were just about gone. after replacement, no more vibration.