Rough idle (RPM constant dropping from 700 to 300) when the AC is on [help]

[natepcbfl]

No codes? Idle dipping when stopped? Dying when stopped? I'll bet its gonna be the stupid VCT solenoids. Common issue and mileage doesn't matter. I had the issue and it took me months to figure it out. At the time I had only seen 1 random post somewhere just kinda talking about the issue in a F-150 forum I believe it was. Here is a short video of it happing to mine, by the time I swapped them out the thing would die every time I stopped. Part numbers are in the video description and they were like $100 bucks for a set of 4, an afternoon with some beers will get them swapped out. Pick up some valve cover gaskets while your at it to.

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[GazV8]

No codes? Idle dipping when stopped? Dying when stopped? I'll bet its gonna be the stupid VCT solenoids. Common issue and mileage doesn't matter. I had the issue and it took me months to figure it out. At the time I had only seen 1 random post somewhere just kinda talking about the issue in a F-150 forum I believe it was. Here is a short video of it happing to mine, by the time I swapped them out the thing would die every time I stopped. Part numbers are in the video description and they were like $100 bucks for a set of 4, an afternoon with some beers will get them swapped out. Pick up some valve cover gaskets while your at it to.

It seem similar but mine only happens on the AC is on. The exhaust sound would also go silent and loud again (even on track mode, active exausht) etc before it happen and I assume it is because the RPM flactuate. It is super random too sometime car idle super fine even when AC is on but most of the time it will flacutaute, drop etc. I found oil leak on my spark plug so ill take it next month to the dealership to replace the O-ring coils gaskit and while at it ill ask them to change VCT solenoid too since it will be exposed once the covers are removed. So they will replace O-ring gasket, valve cover gasket, timing belt and VCT solenoid all 4 since there is no codes to tell which one it is. Only down side is that it will cost around 1350$.

 

[GazV8]

When my AC is on, my idle is higher. It also offsets the idle drop.
Hmm, do you think the custom tune and no catalytic converters leaned out your air/fuel ratio and fried your spark plugs over time? No sense in changing the spark plugs if the tune is off.

Oh no, tune and being catless has nothing to do with this. There is oil leak from the coil gasket. It is nothing major just need to be replaced sooner or later and to replace it ill have access to the VCT solenoid. so it is 2 in 1 fix. ill do it in dealership next month fingercrossed that it will solve this whole nightmare

 

[garbancillo]

I had this same problem with my 2015 Ecoboost. Only happened when the AC was turned on and the engine was properly warmed up before. No problems at all with cold engine.

 

[GazV8]

I had this same problem with my 2015 Ecoboost. Only happened when the AC was turned on and the engine was properly warmed up before. No problems at all with cold engine.

Exactly, did you manage to fix it ? My car is with dealership for 1 week now to change all four vct as a last resort fix :(

 

[garbancillo]

Exactly, did you manage to fix it ? My car is with dealership for 1 week now to change all four vct as a last resort fix :(

Unfortunately! Dealer was unable to repair the trick. After this, a clutch blown up with just 15,000 miles and twice the evap core (among other minor issues), I sold the car.

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