Heater Problem

[NBSHO]

When I have the heater on my idle is rough. As soon as I turn the eatc off the idle evens out. Is it something to do with the air conditioning compressor? It's mostly when the eatc is at the defrost setting?

 

[Ishodu]

It sounds like it could be the AC clutch cycling on and off. Does it go away with it on vent?

 

[betterman]

Have you disconnected your battery lately? If you have you probably need to reset yuor idle. The procedure to do it is in a sticky on here somewhere.