why does my ac blow cold for a while then start to blow warm

I have this issue on a 2006 Silverado and have found similar comments and questions in other forums. Same symptoms. The AC shuts off. If you turn off the motor and restart it's back and blowing cold. For mine, I noticed it shut off during acceleration such as merging onto the highway. We went through the system with a specialist in auto AC. The clutch air-gap is fine, the components are all functioning, there are no leaks, etc. We replicated the shut down issue on a road test. All the way back to the shop it blew warm air but right when we pulled into the garage the AC came back on. Our belief is it's the ECM. The ECM controls the shut down of the AC when you're accelerating to give you full power and is to then restore the AC after you've backed off. Apparently it's just taking a lot longer for it to cycle the AC back on. When you turn off the truck and then restart you've reset the Wide Open Throttle action in the ECM that controls the AC function.

Forgot to add - I turn off the AC when I am accelerating and then turn it back on when I'm cruising again. The AC comes back on without an issue and I don't have to shut the truck down and restart it to get the AC back. Hope this helps.

Update - I reset the ECM. The AC issue seems resolved, and the truck is actually running like new.

First thing I checked was the refrigerant and lines. Was not the issue. Thought it was the blend door actuator, wasn't that. Reset the climate control, not that. Runs great when started and for a period, if it is above 90, 5 to 10 minutes, if in the 80s will run cold for longer. Then stats to blow warm as if the blend door was moving to the warm side, but that isn't the problem. Here is the crazy thing, it went through the normal problem and started blowing warm then I pulled into a parking garage so the outside temp dropped and the system started blowing cold again. No turning off or on still running. CRAZY! S*** blows cold when cold and hot when hot. So my next check was to be the mode door actuator. I'll try resetting the ecm and let you know how it goes.

The AC issue returned after a few days. I rechecked the clutch air gap and found it at the upper end of the acceptable range .030. I pulled the clutch and removed the single spacer. The system has been operating perfectly for the past few days.

Any update on your issue? I have the same trouble with my 2006 Silverado. Thanks