My 99 Yukon Denali Keeps Dying

[litara]

Detail Information about my 99 Yukon Denali:

This past summer (2006) is when my problems all started. I started using my AC in the Yukon and that's when it first died on me. I would use the AC all day and towards the end of work...about 7 pm is when it would die on me. Now I am not saying that that is the source of the problem only that, that is when it started dying. So I stopped using the AC. After that, no more problems. Then winter came along, and I started using the Heater. At first nothing, but then weeks went by and it started acting up again.
When it would die on me...it would happen when I came to a complete stop. At red lights, I evne noticed it happening when I am climbing a hill or going down a hill it will die at the top or bottom while coming to a complete stop. So I took it in for a oil change at Jifffy Lube. They changed my air filter as well. I also bought new tires. I also had my Fuel Pump changed. That is also making a very loud sound. Sounds like rattling.
I don't know what to do. I took it to Anderson Tires here in Riverton, Ut to have them look at. But the gentlemen told me unless it was actually dying out on him as he took it for a test drive he couldn't tell me what the cause of the problem was. Go figure.
I would appreciate all the help I can get on this.

Thank you
Litara

[maxwedge]

Welcome to AF, a complete scan to look at pending codes or issues is in order, too may things can cause this, bad or dirty egr valve, throttle body and/or idle air control cleaning, maybe you should get it to a dealer, sounds like a tire shop is not the best place to take a driveability problem