When it first starts, it idles really high. Then later, it will idle up and down. What could it be? It does need the exhaust fixed, it has a few leaks. Any ideas?

 

Try checking Idle Control Valve.

 

if you havnt cleaned your throttle body out pull off everything and scrub the **** out of it this will fix most 4.7l idle issues

 

Might have to replace the throttle position sensor

 

changed #3 plug. now it idles at 1500 rpm. any sugesstions on how to fix this problem?

 

I had the same problem I took my throttle body off and cleaned it real good. I also changed my IAC sensor because my truck would idle all over and eventually get down so low it would die sometimes. Since doing this I havent had any issues.

 

2003 dodge ram idles too high after changing spark plug #3.

 

You would be amazed on the junk you will have the other side of the throttle body. Take it off and clean real good.