it seems whenever i turn on the air (or front defog) i have a miss or stumble. I always notice this when cruising at a constant speed. If the control is off or in the other modes (besides air or defog) there is no issue. anyone ever seen this before?

 

That is probably the load the A/C compressor puts on the engine. Does it drop RPMs when this happens? The compressor is only engaged when A/C and defrost are used.

 

yea i figure there will be some load and it does happen in a regular interval around every 15 or maybe 30 seconds, but i wouldnt think it would be quite so noticable.

 

Definitely, the A/C compressor will cause the engine to seem like it is "missing out". It is fairly noticeable to me at idle, but I haven't noticed this at cruising. Maybe try taking your drive belt off and checking the compressor. Make sure the compressor pulley spins freely.