I have a Ram 1500 5.7L. It starts and runs for a while idles rough then dies. If i take it on the road when it warms up it will loose power but then when it gets to normal operating temp it is fine. When it gets "fussy" there is a very strong vacumn in the rear chamber of the throttle body. perhaps the IAC? I need to take codes on it. Thanks for any help.

Most major auto parts stores will read codes for free if you have a check engine light on. Possibly it's the IAC but it could also be the thermostat or temp sensor sending a bad reading to the ECM. I would check both. You can check the thermostat pretty easy by removing it and checking to see if that resolves the problem. for testing the temp sensor I recommend you get the Haynes repair manual on your vehicle for location and testing instructions.