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Hey guys,
I'll start off by saying that I have only had my 2002 F250 with 93,000miles for 3 weeks now and I love the truck, but... Last week while I was driving my truck I had the AC on and under acceleration the air would stop blowing out of the dash vents (towards the occupants) and it would switch to the defroster vents. Still blowing cold.
Now today going to work I was driving at about 45mph and I went to accelerate up to 50mph and it chugged under acceleration (Air is OFF)
Coming home from work it got worse it would chug under acceleration and you could slightly hear that it was coming from the engine. No CEL.
The ac changing like that probably relates to a vacuum leak somewhere in the system. I would look around(listen also for the hiss) for cracked lines. This very well could be the reason the truck is running poorly also.
The ac changing like that probably relates to a vacuum leak somewhere in the system. I would look around(listen also for the hiss) for cracked lines. This very well could be the reason the truck is running poorly also.
I agree that it's likely the cause of the A/C problem, but a vacuum leak would be more pronounced at idle than under load.
the pcv valve tube going to the pass side valve cover is bad about cracking from heat and oil rot, but really any vac leak would cause your prob, in case you don't know, take some carb cleaner or start fluid and spray your vacuum lines a couple inches at a time and listen for idle change, when idle changes, you are usually pretty close to your leak. This is prob a small vac leak though, and is probably your a/c problem, but not your driveability problem, I'm a powerstroke man though, so I don't know what to tell ya about your 5.4, I don't have a high opinion of them anyway. Sorry I know this is a ford sight,but I love the 5.3.