I have a 2004 Suburban with a 6.0 liter in it. It has started chugging really bad under hard acceleration from a stop. Not hard enough to spin the tires, just hard enough to pull a load. If you roll onto the accelerator easy, it runs fine and if you are going 20mph or more, and accelerate hard, it takes off like it should.
Any ideas? I was wondering about the Idle air Controller