i have a 05 ram 1500 4x4 and lately when i start it after its been sitting a few hours, it revs up and down. i have know idea why it does this...any help would be great. THANKS!

 

What range, what motor, what mileage?

 

could always try cleaning your TB, and resetting your TBS .you can find that in the FAQ.

also is your check engine light coming on?

 

it revs from 1k-2k RPMS 4.7L and has 80,000 miles on it...check engine light not on

 

kinda sounds like an airflow sensor issue, check the sensors around the TB

 

i would check the tps, and the egr, when you have an egr malfunction or vac leak the computer will try to compensate for it, causing and irregular idle patterns like your are experiencing(although 1000rpm is a bigger jump than normal). as for why it only happens when the truck sits, sometimes when the egr is leaking or another vac source is leaking the hole is very small, many times small enough where after the motor heats up enough the heat will expand the metal/hose and seal it, making it run normal. hope it helps, if nothing else its something you can cross off the list of possibilties

also if it was mass air flow sensor your light would more than likely come on imediately , im not a dodge tech but in most manufacturers the air flow sensor flashes instanly when its malfunctioning as opposed to something like a missfire which has to reach a certian number of faults for the light to come on

 

sbsga is probably right about the air flow sensor, whenever i see the issue there is a light on. I was just suggesting a potential cause from the symptoms.