I have a 2002 Cadillac Escalade EXT, AWD, 6.0L, 30k, on mornings and on cold starts, the engine will rump and and down in a pulsing mannor for a about 5-10 seconds, if the truck is in gear, it lunges up and down like it is stalling for gas, or similar to stalling a manual car. It has also happened at stop lights on occasions and it really makes the truck sound sick. I've taken it to the dealer twice now for the same reason, they report they have not experienced it, the truck is at the dealer currently, and i've asked them to keep it overnight and try starting it in the morning and putting it in gear, and see what it does, it does it EVERY morning, it stays in the garage, 75-80 Degree temperature.
Has anyone experienced this? and if so what can be the cause so that i may notify the dealer.