Here's the scenario.

Puling with my '06 3500 5.9l megacab a trailer at 9300lbs over the cascade mountains on longer trip.

Twice I've thrown a dash light for the coil / spring looking idiot light and have gotten mixed info on what the light means.

This only happens after a long climb and several miles after the decent on the downhill side of a pass.

Bells go off and the light comes on...since I'm on the downhill it's not noticeable on power loss...but on a steep incline it's obvious the power is not where it was.

The light stays on and truck feels slightly underpowered...but definitely lacking power when pulling up a steep hill. After about 2-3 times of driving the truck the light goes out and power restores to normal.

Some have told me it's a grid heater issue. Others have said glow plugs (which doesn't make sense while the truck does fine until on a descent).

I've also been told it's a fuel issue after the transition of using lots of fuel and then letting off the pedal on a decline.

Anyone have an ideas what it could be and then more importantly...how to fix it??

Gotta get this figured out and fixed before I pull again in a few weeks.

Won't be much fun having power issues while climbing.

Thanks all!!