When braking my engine starts idleing rough, especially at the stop signs. Just curious if anyone has experienced this or knows the problem. It idles fine after the brakes are let up on.

Its a 2003 3500 with 130K+ miles

I'm no expert, but check the power steering fluid, pump, lines. The brake system is hydraulically boosted by the PS pump.

I own an 03. Engine warm, idleing, hit the brake pedal, there's an audible difference, but certainly not an erratic idle. I would check the fluids like the other poster mentioned.

there were some faulty hydroboost cylinders.