2015 dropping rpms at stop

[Aggiesrok]

2015 3.5 non-turbo, 107k miles, 2nd Limited. Had car 4K miles, initially it always did this after warming up at stop: rpm’s drop to about 400 & surge back to 700-800 & it cycled like this.
Replaced faulty AC compressor, Seafoamed throttle body, cleaned MAF and replaced plugs. Now it only does it when AC fan is on high or 1 below high. Also after hard acceleration it does it. No CEL’s.
My next option maybe new throttle body.

 

[J_C]

Welcome to the forum!

2013-2015 with the 3.5L NA have a known issue, see this video and the TSB 15-0149. I don't know for certain that this is the problem but seems possible...

15-0149 Ford Auxiliary Emission Control System TSB

15-0149 Ford Auxiliary Emission Control System TSB

www.tsbsearch.com

I experienced this on my '14 but only after a single *bad?* tank of gas, then it went away. No other drivability issues on that same tank of gas.

 

[GerryEX]

Check this:

Random RPMs drop, engine seems want to stall

Recently I´ve been noticing a random drop in rpms, below 500. At first I noticed it on D on stop and go traffic, the engine seems to want to stall briefly, then the rpms got back up to 600+. Then today it happened at Parking. I turned the A/C on and off and the rpms seem unchanged, So I don´t...

www.explorerforum.com

Start with the throttle body. We will chase the intermittent idling issue in this new Explorer after the mounting of the new tires and wheels tomorrow.

 

[Ironworker40]

Are you sure it's not the a/c compressor cycling? The a/c compressor runs for defrost as well as a/c.

 

[Aggiesrok]

I did the reset/relearn for the throttle body and it’s still doing it. If I get Fordscan, can I update the PCM software myself?