Hey everyone.. I have a 2004 (new body) with a 4.6 engine. The AC will be working fine for a while during a drive, and then it will just start blowing stale uncooled air. Not exactly like it is coming from the heater but more like it is blowing recirculated warm air from in the cabin. I found that when it does this, if I stomp on the gas hard for a few seconds and then let up, it will magically start blowing ice cold again. I had the refrigerant recharged when I got the truck and it was having this problem which solved nothing but did make it blow a tad colder when it was blowing. All of the directional switches work properly (where I want the air to go, floor dash or defrost)... It almost seems to me like there is a vacuum operated part in the system that is not kicking on/off properly but do not know enough about ac operation to know what or where it may be. I have read a lot about blend-door issues on these years but it seems like the main symptom of that (besides blowing wrong temps) is that the air does not go where the selector switch is telling it to which is not what I have going on. I do not hear any "thuds" or "clicking" when I move the selector switch around either...

Does anyone have any ides on where I should look?

Thanks everyone!
John

 

The air gap on the compressor is probably too large due to a failing pulley. Check the air gap with a feeler gauge.

 

I have similar problem, except right at the end of the "cooling season" last year my a/c compressor died. Now, I'm a big boy and sweat year round, so I had it replaced by the local Ford dealer. It didn't seem to cool very well in the fall, and I took it back, did some internet research and tried to get them to make it better. However, the brand new compressor.....with a blend door change.....still does the same thing you just described! Ice cold for a while, then "tepid" cool air, then accelerate away from a stop sign or something and it's ice cold again????? Mine is an 05 SuperCrew w/4.6. What's the "air gap"????

 

The clutch on my work truck caused the same problem.
It was slipping and not turning the compressor.

Measure air gap between A/C clutch and A/C clutch
pulley mating surfaces at three equally spaced locations with a feeler gauge.
The smallest air gap measurement must be within specified limits for air gap. Add, remove or replace shims between A/C clutch and compressor shaft end as necessary until smallest air gap is within 0.4-0.7 mm (0.016-0.027 Inch) .
These numbers may be different for your vehicle.
Check with a mechanic for your specs.