idel question

[shocker998md]

so the other day i was letting my truck idel to cool down after driving it and i noticed that it was just slightly reving up and then coming back down. Now i just did the bb mod and im not sure if my truck has always done this. I was thinking about doing the idm mod to smooth out the idel more but i just want to make sure if theres something that may be comming about from this. The previous owner had the CPS changed but maybe thats going out again? I use lucas in every tank and put diesel kleen in it ever other tank to keep it good and clean. Has a clean air and fuel filter too. Hopefully its just nothing but hey i figured id ask, thanks guys

[pipelayerjdh]

How much does it vary and what is the frequency?

[REDPOWERSMOKER]

WAS YOUR AIR CONDITIONER ON OR ANYTHING MINE DOES THAT WHEN THE A/C OR DEFROST IS ON

[shocker998md]

no the ac was not on, it was just going up and down maybe 100 rpms but it was still noticeable. Im going to take the truck to the dealer about the cps recall because the truck is still acting funny when i drive it down the highway for a while. It just falls on its face and then then ill pull over, shut the truck off, and when i turn it back on its fine. No codes or anything