I have a 2003 3500 dually diesel automatic 4X4. At 1400 - 1700 rpms I can feel a vibration in the gas pedal, that is more pronounced at 1600 rpms. It doesn't matter what speed I'm going or what gear I'm in. Anybody have any suggestions to what might be causing this?

 

i would start with the simple things, tires, u joints, rims that sort of thing. does it do it only under power or will it do it in neutral coasting? if you are sure its engine related i would check the crank balancer, or fan.

 

Thank you for your suggestions: I'm pretty sure it's the engine, considering it's related to rpms. It doesn't matter what speed I'm traveling, or what gear I'm in, including neutral. I'll check the fan and crank balancer, and post my findings.