Rough idle with auto start/stop disabled and A/C on

[Cones169]

Does anyone have a issue when the a/c is on and and the auto start/stop is disabled. When i first start truck and am just idling in drive the rpm's jump up and down like it wants to stop like when using the auto stop. It eventually goes away after driving for a small bit and then coming to a stop.

 

[baptizo]

Nope, no issues and I always put the truck in Sport mode after start-up.

 

[TxCOR]

I have noticed this too, but its not a big variation in RPMs. I haven't really paid much attention since there hasn't seemed to cause any actual driving issues...

Curious if anyone has dug into this and found it to be something greater than just a cold rough idle.

 

[Cones169]

I made a appointment with ford to check it out. I’ll let you know what they say

 

[rcadd1ct]

I was having this and the dealer cleaned the intake and it helped for about 7k. Now I get it again. Almost at 30k now. I might change plugs soon.

 

[quikag]

New ‘19 less than 1k miles. It’s hot out here in DFW and when I come to a stop rpms are around 500ish. Then I guess the AC compressor kicks in and rpms jump to 750 or so and if I only have my foot lightly on the brake, it’ll try to move forward a bit which is a bit disconcerting. I push a touch harder on the brake and all is well. The rpms don’t fluctuate after settling at 750rpm.

It’s kind of annoying actually, so now I just push a bit harder on the brake while waiting at a light and ignore it when the rpms jump a bit.

 

[91Eunos]

I do have that too... was going to take it in to the dealer to have it checked out, but now that you mention it, it’s only been happening since I had the cam phasers replaced under warranty. I assumed it was a loose vacuum fitting or something similar, but may be an “update” to the ECU that changed an idle setting.

I always have the engine shutoff disabled but will try it enabled. Will also try it in Sport mode to see if it goes away.

 

[sdspa]

I have a rough idle. It’s more of a feel than seeing the rpm needle move. And it’s when the AC is on or off, and doesn’t matter if stop-start is on or disabled. So I think it’s different than a change in idle due to the AC compressor. I really hope this isn’t a precursor to the cam phaser problem...

 

[Fastback89]

I disabled the auto start stop with Forscan and my 18 idles smooth ac on or off

 

[docskeet1]

I have an 18, ESS disabled with Forscan. My idle seems too slow at times on a hot day with the AC on and the truck is cold. Smooths out/goes away when the truck warms up. Pressing on the brake has no effect.