Replying to Sore quads while skiing

I'm having a problem when I ski with quad pain, pretty much halfway down the first run. Just feels like I've been doing squats for 4 straight hours and I get jello legs, like 30 seconds after I'm off the lift.

I've only tried two setups - the first when I took lessons 2 years ago, I skied 10 days in whatever basic Lange/Rossi rental gear. No problems.

This past season I bought my first setup, full tilt classics (they fit my feet the best) and some atomic panics. Jello legs the whole day, I can only ski about 2 hours at the most before I feel like my legs were going to fall off. I skied about 40 days over two months, so it definitely wasn't just "getting ski legs again" or whatever.

I did some quick research, looks like forward lean might have something to do with it.. being too far forward and making me want to lean back to compensate, or something.

My boots have cuff spoilers and the little plastic clips at the bottom of the cuff, both to adjust forward lean. I took them both out but can't really feel a difference just standing in my boots, obviously I'll have to ski a bit and see if it makes a difference.

Any other ideas or things to try? Figured I'd ask now, in case I should look at different gear before the season starts, so I can get some deals.