help!

They could possibly be sealing too tight. When you are slamming the door, there is no place for the air to escape, and the pressure makes it hard to shut the door. If you havent already, try rolling the windows down and shutting the door. If doing this makes it easier to shut the doors, then as I said before there is no place for the air to escape. Newer trucks have vents on them to release the air. My old s-10 had a release vent on the back of the cab, just below the rear window.

My old '72 Chevy is kinda hard to get the doors shut with the windows up.

Could be the new rubber.Had same trouble with my F-100.Called a friend and he told me to get the doors closed as tight as I could and give the rubber time to compress.It worked. After a while I had to adjust the latch so it would close tighter.

You can install a PR valve. (pressure relief valve). I don't know about other cars, but on a 88 to 92 Grand Prix. the PR valve is the size of a deck of cards.
Imports might be smaller

I had to slam my truck doors on my 54 sometimes 2-3 times ... it was bugging me no end - I was sure I needed to adjust the hinges, etc. BUT! willys36 told me to try door latch repair springs - a simple thing that cost me $5 (I bought 3 to have a spare) and took about 3 minutes of my time ... I also put door bumpers in (another $1.15) and I was STUNNED at the difference it made!

Both doors close with just a light toss and man, am I ever grinning every time I close 'em now.

I agree with Lash, give the rubber time to set.
The same thing happened on my Vette. Also there is a lube to put on the seals to help.

I will third the new rubber seal issue. I put the door seals on my S-10 about two months ago now. At first you really had to slam them. Now you just have to kindof slam them. I figure in two more months they will shut perfectly.

Just give it some time.

Chris

I guess adjusting the tension on the latch mechanism is too obvious. I think the weather seal material will compress with time. In the mean time, you don't need door poppers which is good.

I had the same problem when I replaced the rubber on my camaro.It turned out that the regulator on the window needed to be readjusted.I found this out because when I'd roll the window up all the way I had to press down on the back corner of the window to get it to close properly.After some work I was able to get it to close properly.It may be worth looking into.Bruce