Truck shudders at idle with A/C on

[Laser145]

Hey guys

Just picked up a new 87 R10 (305, 700R4, stock exhaust, emissions, etc).

It runs great, no codes from the computer... However... When the A/C is on and you're sitting at a stop light the truck will shudder every 15 seconds or so... feels like it's going to die, but never does... just shivers for a few seconds then the idle picks back up.

Also, When I operate the power windows, the battery needle drops... you can tell it's a strain. Is that normal?

Cheers
Taylor