Toilets, Sinks, Showers, Tubs and Disposals - Decreasing pressure in faucet

I have a delta single handle faucet with side sprayer (Delta at Lowe's: Stainless Steel Kitchen Faucet with Side Spray (http://www.lowes.com/lowes/lkn?action=productDetail&productId=274209-72981-11946-SSSD&detail=cr&lpage=none)) I installed it, and everything went ok. Since then, the outlet pressure has decreased gradually. When I first fired it up, the pressure was great, and then it suddenly dropped, like a check valve or restrictor engaged (this is with the aerator and normal restrictor not installed) and it's gotten worse since then. I do have really hot water. My question is, does anyone have any ideas as to why this is happening? Is there a way I can reverse the affects? Any input would be appreciated.

Does the sprayer work properly and does it have the same pressure issues?Are the effects the same for hot and cold?

Normally beyond the aerator you'd want to check any valves at any point for obstructions or loose washers.Does this faucet have traditional supply valves or does it have brass stop valves?How old are they?

Did you use stainless flex supply lines?

I'd take apart the assembly and see if there was any grit etc in the seats and springs and check the diverter as well.

I isolated the problem to the diverter valve that sends the flow to the sprayer or the faucet. Now I have to figure out how to fix it, or just replace it.

Delta diverters are available pretty much anywhere that sells plumbing repair parts and replacement would be the best option.

Since this is a new unit I would bet if you called Delta they'd send you one for free.