kaihila

My Mustang's been idling whenever I roll up the windows.

I've had both the battery and alternator replaced twice in the last 4 months. I took it in to the dealership about 3 months ago because my mustang was idling whenever I put it into park & drive and when I started the car. They said they cleaned out the throttle body and it fixed the problem. Then, a month later, the alternator died out (for the second time) Now, 3 months later, it's starting to do it again after alternator #3, whenever I roll the windows up. It also happens when I'm at a stop light. Any idea what it could be? Sounds like a power issue but what? Thanks in advance for your help.

04hemigtx1990

Any Engine Lights On?

kaihila

No lights or anything. And to avoid any confusion I mean the car idles roughly. Like the RPM's suddenly drop and come back up again. The dealership called it "idling".

04hemigtx1990

My dodge ram use to do that, Then I put a power programmer on it and it fixed the problem. Maybe because the advanced timing? I've got a Predator U7145 Programmer for sale for $280 shipped if your interested. I just gave $440 for it 2 months ago and sold my mustang last week. It's unlocked and ready to go. Just let me know.

Alec

I've noticed recently that when I use the windows, the RPMs dip slightly. It's usually when I'm at a red light and hasn't been a problem yet. (knocks on wood). Not sure what it is exactly yet but I think I'm due for a new battery so hopefully that covers it.

kaihila

It happens when I'm at a red light also. I have a brand new battery and alternator in there. I guess this is a much bigger issue.

Alec

Do the RPMs just dip or does it stall out or anything like that? When I roll down my windows it just dips a little bit. It's just something I noticed one day and doesn't affect the car much. I always assumed it was the battery because occasionally on a very cold day it doesn't fire up as quickly as normal. Hopefully it isn't a major thing

incorrigible

The idle drops because of the additional load being placed on the alternator from the power window motor. It should not, however, drop the idle significantly. If it's stalling from this, it's something else wrong such as a dirty throttle body or something. The strength of the battery should have no effect on this.

kaihila

The idle dips but nothing drastic. It just started doing this though. The car has not stalled either. And I just had the throttle body cleaned about 2 months ago.