hard shudder under certain conditions...

[Jrgicehc]

I am getting what i am going to call a hard shudder when i do one of these things. turn on either blinker, turn on the headlights and put on the highbeams. it happens most of the time with the blinkers and only sometimes with the headlights and the highbeams. the one last condition that has to be met is my foot needs to be in the throttle. the more I am into the throttle the harder it will shudder when it happens.

for those who think I am experiencing a fishbite, ive read the descrption of what a fishbite is and this is more like a whale bite when it happens. it rocks the boat.

[Mark Rinker]

Sounds like you are getting a voltage drop, and your fuel delivery system and/or electric injection pump are being affected.

I would start by cleaning and treating all battery connections and electric system grounds with dielectric grease. If that doesn't fix it, I'd have both batteries load tested, and the alternator tested.

The wiring for the headlights and turn signals is undersized on these trucks...search this forum for re-wiring instructions.