I have a 2005 Mustang V6 and lately I have noticed that when I am idling at a stoplight, about once every 60secs the rpm's will drop by a few hundred.
Its just for a sec or 2 then goes back to normal rpm.

I was working on it this morning and noticed that when the rpm's drop like that, its the same time that the electric fan kicks in at the radiator.

I hooked up my code reader and can see that when the ECT temp hits 95degrees, it starts the fan up. I am guessing the fan is failing and drawing too many amps.
The battery and alternator is brand new so I dont think the issue is with that.

Is this an indication that the fan is about to fail? its still the original fan the car came with.

The car never stalls out, just feels like its going to. When it happens I usually pump the gas to get the rpm's back up lol

Thanks
Any advice would be greatly appreciated

 

Welcome,

Have You Cleaned MAF & T/B Recently? If Not I Would Clean Both With Proper Chemicals T/B Cleaner & MAF Cleaner & Then Disconnect Battery To Reset PCM & Drive For a Couple of Days To Complete a Drive Cycle & See if That Helps. Also I Would Pull Connector at Cooling Fan & Look For Signs of Overheating Wiring & Poor Connections Clean With Electric Contact Cleaner.

Also A good Time To Add Some Good Fuel Cleaner To Fuel System. Ford Loves To ADVISE Techron Additive!

A Good Start I Think. I Guess You Are Not getting Any Codes. You Might Also Let Car Warm Up & Watch For The 95 Degree Mark When Idle Drops & See if A/C Compressor is Cycling at Same Time Causing a Load & Bringing Idle Down. The Cleaning I Advised May Help Engine Respond To Load Quicker Regardless!

Anyhoo, That is What Pops To Mind.

Kc

 

I havent checked the MAF and Throttlebody yet. Good idea!
I will inspect the fan a bit more this weekend

There were no codes thrown and the A/C was off

 

Be Advised The Compressor Can Cycle While In Defrost Mode on Many Vehicles. Not 100% on The Stang at The Moment But I Think it Does!

KC