idle drops way down then goes back up
 

a fellas iam new to the site
so i got a 2006 e-150 econoline it keeps dying on me when its idleing the idle drops way down then go back upis a problem if it were in drive it would die but in park and running idle will drop just before the point of dieing then idle go s back up i put my code reader in and no codes come up and check engine light NOT on also i replaced the battery and later that day when problem with idle also its runs fine when it cold but when it warns up is when idle is a problem van has 260.000 miles on it no other engine problems has fuel injection
does anybody have any ideas thanks

it's either the idle air control or throttle position sensor or it could be both. there is another thing that could be causing it to run rough or not at all when warm is you could have a vac. leak somewhere. lets start with the vac leak first get a can of choke and carb cleaner and spray it around the bottom of intake manifold and listen for any changes in rpm if it smooths out and runs normal then that's the problem.

after checking all of the above items.
then check/clean your air inlet sensor and the next item to check/clean is the exhaust o2 sensor(s)