As far as I can tell their is no draft coming out of the fine mesh plank
vent on the pilots side.

That is so weird. Is there something blocking *that* opening? I just
can't imagine what's causing that kind of strong air-flow.

The Cherokee Chat is the Cherokee Pilot's Association on-line chat
room. You've got to be a member, but it's worth every penny to join,
and then some. See them he http://www.piperowner.com/

With over 4000 Cherokee owners in the organization, you can always
count on getting an answer on ANY Cherokee question you might have.
And they have the BEST fly-in of the year. See info on that he
http://cherokeeflyin.com/

We've attended the last four, and intend to go again this year.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"