Background 2002 Ram 1500 4.7 V8 2WD

Ok after starting my vehicle the idle RPM's jump to 1500 about every 5 seconds non stop until I start driving, also continues while in drive at lights stops ect. Been hearing alot about idle air control valve/sensors.... Any ideas, How do i find out if my engine is sending out a code?

 

if it is sending a code your CEL or check engine light will come on. with your year model truck to read the code turn the key to the on position then to the off position three times and on the third time leave it on the on position