Fluctuating RPM's...

I haven't seen the rpms fluctuate up in down like that..I can see this happening when the ac is on. The only time the rpms go up and down is when shifting from p to R or D.. I always let the truck idle till the rpms drop which is about 10 to 15 seconds.

I don't believe the self cleaning has anything to do with the rpms just the clicking sound you hear when your stopped..

I think the atkinson cycle has particular womp womp sound when it's engaged mostly when your cruising in at a low rpm and your lead foot is off the pedal.

 

When stopped idling I notice sometimes rpms kick way down to about 600 and sounds like my old diesel BMW. 3.0L. Wishful thinking that i had a twin turbo diesel taco

 

Mine only does it idling in park. In drive with my foot on the brake at a stop light or stop sign it does not bounce back & forth at all. Should I be overly concerned and take it to the dealer or not...? Basically thinking out loud on the keyboard, I know it's my truck & ultimately my decision. Just trying to get feedback from more experienced and brighter minds than myself.

 

Doesn't hurt to ask. But if I was you I wouldn't worry to much about it since other people are having the same (so called problem?) unless it gets worse later on in the future I would then take it to the dealership.