Engine surges (Dodge Dakota)

I have a 2004 Dodge Dakota with the 4.7liter V8 and 30,000 miles on it. A few weeks ago, when I started the engine in the morning the engine surged up to about 1500 RPM when it first started, then when idling, the engine would surge up to about 1200 RPM and back down to 400-500 RPM. Once the engine has warmed up, the surging is still noticed when idle at stop lights.

The problem doesn't happen everyday, there are some days when the engine starts and idles normally. I also notice that once the engine is warm, I can rev up the engine to over 2000 RPM and it does go back to idle, and instead cuts out. However, after I restart the engine, the surging problem goes away (for that time, but comes back another day).

I have cleaned the throttle body and used fuel injector cleaner and haven't noticed any change or seen any improvements.