Unstable RPMs when vehicle warms up.

Once it hits running temperature, the RPMs become so low that the vehicle almost shuts off. It also sounds as if only 3 out of 4 cylinders were working, but not so bad as to be a missfire. Any idea on what might be causing that problem?

crwdns2934089:0crwdne2934089:0 crwdns2934093:0crwdne2934093:0

crwdns2934109:0crwdne2934109:0

crwdns2889612:0crwdne2889612:0 0
crwdns2934285:0crwdne2934285:0