Q: Engine running hot with heater issues

I let my dad borrow my car yesterday so he can go to Reno for the day. We live in Sacramento, CA so it was a total of about 230 miles round trip. When he got back last night I could smell anti-freeze. It didnt appear to be overheating or leaking at all and he said he hadnt had any issues. So I didnt think much of it. Later when I left though, I could tell something wasnt right. Theres a slight jerk and/or a engine bogging noise for a split second when I first give it gas or let off the gas. My first thought was a bad engine or tranny mount, but that doesnt explajn the bogging noise. Then I noticed the engine running hot and heater issues. Its not overheating but if I turn the windshield defrost on it just blows cold air and my temp guage goes a little over 3/4. If i aim the air anywhere else like the feet, face, etc. the temp guage will go down to 1/2 but the air barely gets warm. Before yesterday the engine ran smoothe, heater got hot, and temp guage never went above 1/2. Any advice?

My car has 95000 miles.
My car has an automatic transmission.