Weird Suspension Problem

Lately my car has been riding horrible. The front end shakes really bad. But its not the usual shaking, like from side to side. This is up and down. And it happens even on flat roads that were recently paved, so the ride should be excellent.

One of my wheels does have a slight dent that makes it hard to balance. I learned this the last time I got tires. It's not that bad. It does make it feel unbalance at times though, and I can feel the tire wobble a little which I'm used to. The problem is not from this as far as I can tell and it dosn't bother me much. I also had an alignment when I got new tires, and they were all balanced pretty good.

So I took the car in to get an oil change today, and asked them to check out the front end to make sure things like ball joints, tire rods, struts, etc. were all tight and in good shape. The car checked out with flying colors as far as that goes. The mechanic even took it out on a test drive since I didn't believe that there was nothing wrong, and he came back saying it rode fine just that the roads were shit because it's so cold here (single digits, gets below 0 at night).

The problem has been happening for a few weeks now, even when it wasn't as cold as it is now. The feeling is not normal, I know how my car is supposed to handle but he insisted there was nothing wrong.

My question is...could there be something wrong in the steering that would make the car shake up and down in the front? It seems to be worse at certain speeds, like between 25-40 mph. Interstate at 70 mph drives pretty normal. Any thoughts? Thanks guys.

Maybe that dent got bigger. Could also be the struts going out. How long have those been on?

Maybe that dent got bigger. Could also be the struts going out. How long have those been on?

Usually when I noticed the problem with the dent in the rim, the wheel would shake side-to-side like it wasn't balanced perfect. This is more of a up-and-down type of shake, so I didn't think it was related to that.

The struts are stock and to my knowledge have never been replaced, but the mechanic said they were fine and they checked out before when I had the alignment a few months ago.

When I got my new tires, the first time on the expressway, the car was actually shaking up and down like bouncing. It was really bad and it made me laugh and then almost dump the tires. So I know how that feels.

I know you didn't just get tires, but just thought I'd share.

That's really fucked up. Is there any ice or snow frozen in the rim? That will cause them to not ride smoothly.

That's really fucked up. Is there any ice or snow frozen in the rim? That will cause them to not ride smoothly.
I made sure that wasn't my problem when I took it to the manual car wash a week and a half ago and cleaned the wheels and everything really good. At that time, it was decently warm (above freezing) and I took it on the interstate after to dry it off so it didn't freeze. I'm still stumped on this, thinking about taking it to a Mitsu dealer and forking out an hours worth of dough to have them take a look at it. I had originally taken it to a Chrysler dealer where I know the mechanic pretty well, so I trust him but something isn't right.