My wifes Tahoe keeps dying.......

My wifes Tahoe just up and die when you start it up. if you shut the A/C off and don't put a load on it with the P/S it will do okay but if the A/C is on it will stall every few seconds until you get on a stretch of road that wil let you build up the RPMs. It also uses a quart of oil every now and then. I have no idea where it goes. No drips, smoke anything. The dealership told us that they had to do a "consumption test" before they would do anything else. Of course we told them we knew it was using a quart every so often but you can't narrow it down or put a mileage on it. It simply comes and goes, usually on a trip.

The stalling is killing me, every stop sign for the first few miles. We've had the fuel filter replaced. I thought maybe an intake manifold leak could cause both it and also the oil usage.

HELPPPPPPPP!!!!

What year model Tahoe is it? My 2000 model (new style) would try to die when in gear, at idle with the air on. The dealer cleaned the throttle body, worked like a charm. Though that may not be your issue, maybe it'll give you something to go on. Has the shop been unable to diagnose the stalling problem? Surely it would act up while they had it.