Carbon monoxide poisining!!!

["Joseph M. Shaw, II" <MikeIIDC@domain.elided>]

Help!

I know I always have a new problem to resplve, but my Scout II is so bad
with CO that I drive it for five minutes and smell like the stuff for
the rest of the day!  My eyes are burning whenever I drive it, and it
seems that if I roll down the windows it gets worse!!!
I have a very rusty hard top on my '73 Scout II, and the liftgate has
fallen off, so that is an open vent for the stuff to suction in at
highway speeds, but I've noticed that it comes in constantly-sitting
still idling or going down the highway at 70.  What is the best thing to
do to prevent this?  If I get a whole new exhaust will it go away?  I
bought some Lucite to rig up a home-job liftgate, but don't want to put
it on, as I now am not sure if that is how it is getting in.  If it
isn't, then I will just be trapping the stuff inside with me and not
letting any circulate out!
New exhaust and seal the rear, or as rusty as my body is (well, the
Scout's body, though I'm no spring chicken!), am I bound to suck some in
any way?

Thanks!

Michael