Back in May, I replaced the ice maker and water valve on the refrigerator. Everything was working fine until about six weeks ago, when I used the water dispenser. The water stream quickly went to a trickle with vibrating as if there was air in the line. Knowing it was about time to replace the water filter, I did that. Of course, there was more rattling as is normal with that replacement. But it has not gone away.

Water through the dispenser is still only a small stream. The ice maker still turns out ice ... and sometimes when filling is accompanied by vibration, sometimes not.

Is there a stopped-up line or is it only air? I noticed that at the bottom from of the refrigerator behind the toe grille there is a connection. Is this a check valve of some sort? Is it a point at which to attempt something else?

Thanks.