Every once and a while my 2003 1500 5.7l acts like it wants to stall but then brings it self back to a good idle. It normally idles between about 500-650 rpms. When I acts like it wants to die it will drop below that for a couple seconds and then goes back to normal. What could be causing this.

 

Try cleaning the throttle body

 

I see this answer often so just as a matter of clear indication what is meant by clean the throttle body? I think it means remove air filter assembly, use rag and cleaner on sides and flaps, open the throttle and spray inside then wipe what you can. Reinstall air filter and done. Am I right is that it?

 

You want to pull the IAC motor, clean it, and it's well too. (go gently on the pintle... you don't want to move it, or break it. )

They like to accumulate crap in the IAC well, and that can change air flow characteristics, and confuse the PCM.... It can also plug up, or completely jam the IAC, so that the engine idles fine once it warms up..... but, getting it there is a drag.

 

yes to all the above and check vacuum lines egr hoses and hose clamps going into intake manifold. may have a small leak.