Acceleration and Idle problem

I have a 95 Cougar XR7 w/ a V8. About a week ago I was driving on the Interstate and had to slam on my brakes and veer a little into a grassy median to avoid being slammed between two Semi trucks. As soon as I got back on the road and accelerated I instantly noticed that something was wrong.

It felt like all the pistons weren't firing and acceleration was kind of rough. I changed all the spark plugs and a few vacuum hoses hoping it would be a quick fix. Besides needing to change the valve cover gasket (which I know probably isn't the cause) I can't think of anything else to do.

Occasionally it will run alright for the first couple of minutes, but then it will get rough. Acceleration has gotten horrible. If I gun it, it very slowly works its way up, and after it hits 2000 rpm it will take off and run smooth for a bit till it shifts into a different gear again.

I don't really know too much about cars just some basic stuff, so any help would be greatly appreciated.

Check the air filter.
Check the entire air intake pathway for blockage/debris.
You might also try cleaning your MAF sensor.

If after checking everything above doesn't fix the problem, I would check the cap and rotor also make sure the distributor hasn't loosened up and repositioned itself.