I have a 2000 XJ 4.0L 4x4. I noticed here in the past few days when I go above 2200rpm the ac wont blow as hard. If I have the fan speed on 3 and give it gas to 2200 it feels like it blows at a speed 1. when I let off the gas it goes back to normal. Hope this makes sense. Any ideas why and how to fix this? Thanks for the help.

 

Hmm..I wonder if the vacuum lines have anything to do with this. My buddies WJ has a similar issue and it's due to a vacuum leak. Might be worth looking into.

 

Yup.

 

I have a similar issue except when I accelerate under a load going up a hill or merging on the freeway the air flow will kick into the defrosting mode and blow next to the windshield. Just one of many things on my list to diagnosis ... always smiling thou ... let me know if someone has a suggestion

 

Yours is a vaccum leak.

 

I though it only controlled the blend doors no the motor speed.

 

Exactly when vacuum decreases more air flow is directed towards defrost thus decreasing air flow to dash vents.

 

It's frustrating I have check for vacuum leaks and have yet to find one, have used engine starter fluid, check all the lines I can find to make sure everything is connected. I was thinking it was perhaps a faulty check valve or the flap that controls direction. So if its affecting the air controls would I find that behind the dash.

 

Here ya go girls:

 

thanks for posting the diagram ... plan on checking those lines today