Ecoboost A/C Fan Speed Changing + Idle Vibration/Shudder

[chewie]

I just bought a new base a/t ecoboost a couple of weeks back and it has about 700 miles on it now. Loving the car so far but there are a couple of things that have been worrying me.

I noticed earlier this week that the A/C blower fan seems to change speed on its own as if I was changing the speed of the fan myself, but it's doing it on its own. Sometimes it speeds up and then slows down and then up again a second later and it's a bit annoying since the A/C blower just doesn't stay at a constant speed.

Also, I noticed when the car is at idle especially after it's been sitting overnight there is a pulsating engine vibration/shudder that occurs every 1-2 seconds that you can really only feel when stopped. It appears to go away after driving for 10-15 mins. It's not terrible, but it's noticeable. Not sure if it's just the 4-cyl engine.

Anyways, I just wanted to know if the two things above were normal occurrences or if I should take the car to the dealer to get checked out.

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[jasonstang]

I do notice my V8 would rock when the compressor for the AC kicks on. I can even hear it in the idle change.

 

[Ebm]

.

I just bought a new base a/t ecoboost a couple of weeks back and it has about 700 miles on it now. Loving the car so far but there are a couple of things that have been worrying me.

I noticed earlier this week that the A/C blower fan seems to change speed on its own as if I was changing the speed of the fan myself, but it's doing it on its own. Sometimes it speeds up and then slows down and then up again a second later and it's a bit annoying since the A/C blower just doesn't stay at a constant speed.

Also, I noticed when the car is at idle especially after it's been sitting overnight there is a pulsating engine vibration/shudder that occurs every 1-2 seconds that you can really only feel when stopped. It appears to go away after driving for 10-15 mins. It's not terrible, but it's noticeable. Not sure if it's just the 4-cyl engine.

Anyways, I just wanted to know if the two things above were normal occurrences or if I should take the car to the dealer to get checked out.

Do you have the temp set to a certain degree? Also, any hands free calling? The fan speed slows down when on the phone.

 

[chewie]

I do notice my V8 would rock when the compressor for the AC kicks on. I can even hear it in the idle change.

The pulsating vibration/shudder appears to occur even if the A/C is off. It's not major and it's barely audible. I don't know if it's just part of normal 4-cyl engine noise/feel or something more.

Do you have the temp set to a certain degree? Also, any hands free calling? The fan speed slows down when on the phone.

I have the base ecoboost so no automatic climate control and I have not been on the phone when it's occurred.

 

[garbancillo]

The variation of the fan speed has been regarded as normal, it happens both in the EB and GT. Further to your concern with idle, please, do check if idle drops below the normal rpm level when you switch on the clmate control with the engine at normal service temperature. Mine does it since it came out of the dealer (a year and half old now). It has been said that it is an ECU matter (it would appear that ECU does not send a signal to rev up idle when engine is warm and the AC is switched on, but the fact is that after Ford service has flashed the ECU twice to solve the problem, the matter is still there).

I figure out that your problem with idle is somehow simmilar to mine and probably connected also to AC. Would appreciate if you could check this. Thanks!

 

[jasonstang]

My Mustang is probably the first car I can actually feel when the AC is cycling on and off.
It's not a smooth transition, the whole car just rocks.

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