Slight problem...

[Matto]

Okay, my car is a 1997 Mustang GT, Manual, with about 60,000 miles. I was noticing tonight while sitting in line waiting to get food that when just sitting my car idles around 600 or 700 RPM's which I'm guessing is normal? Well I was noticing every once in a while that it would drop to around 500 real quick and make a shuttering sound which sounded like it was coming from underneath the dash but I'm not for certain. It only only do it for a second then return to normal. I also noticed sometimes while doing it, my lights would dim for a second. Anyone have any ideas what this could be?

 

[TomBadger]

Did you have the heater on? If your climate controls are set to anything but OFF or VENT, the climate control pump kicks on every few minutes and causes a drain on your electrical system.

 

[wht99gtconv]

Okay, my car is a 1997 Mustang GT, Manual, with about 60,000 miles. I was noticing tonight while sitting in line waiting to get food that when just sitting my car idles around 600 or 700 RPM's which I'm guessing is normal? Well I was noticing every once in a while that it would drop to around 500 real quick and make a shuttering sound which sounded like it was coming from underneath the dash but I'm not for certain. It only only do it for a second then return to normal. I also noticed sometimes while doing it, my lights would dim for a second. Anyone have any ideas what this could be?

I had a bbk cai on a 98 gt, and it made my rpm's go crazy.

 

[Matto]

Did you have the heater on? If your climate controls are set to anything but OFF or VENT, the climate control pump kicks on every few minutes and causes a drain on your electrical system.

Well would it make the rattling noise like I described? I am pretty sure nothing was on because I had my window down, could be wrong though.