I have a 2012 3.7 125,000 miles auto mustang. If I’m idling while parked and the fans or A/c kick on the cars idle will drop, causing the motor to stumble like itsgoing to die. The car returns to normal idle and will continue this as things kick on and off. Ive looked at the mustang forums and found others with the issue but no solutions. Ive cleaned the mass air flow and throttle, the car has new spark plugs and no noticeable vacuum leaks. What could be causing this and how can i fix it?
thanks
no noticeable vacuum leaks.
They're not always obvious.
Do a thorough test and make sure you're not missing anything.
i was wondering if maybe it was a power drain when things kicked on also.
The battery should be able to cover brief power drains like that, unless it had a poor connection.
Make sure the terminals are clean & tight, and grounds are in good shape. You could have your battery + alternator tested too.
The AC compressor may be on the way out and pulling down the idle when it kicks on.
but what about the fans
Those too, good call @mmj. I think you're probably correct about the vacuum leak, though.
I’ll do a thorough check to see about leaks.
i was wondering if maybe it was a power drain when things kicked on also.