RPM Drop when Idle

[Grkstang]

I've noticed a couple of times now when I'm sitting with my foot on the brake while I'm idling a stoplight that the RPM will drop to about 500rpm (it normally sits around 800rpm at idle) and the engine will "rattle" as if were going to stall.


I guess it might be a vacuum leak... but not sure.

Has anyone experienced this or know what it might be?

Thanks in advance
​

 

[onlycodered]

This might be the IAC (Idle Air Control) valve. My friend redlawyers recently replaced the IAC valve on his 2000 GT and it fixed his idling RPM issue. Also, here's a video on how to tell if it's your IAC valve: [ame=http://www.youtube.com/watch?v=oNO8GCN8jQA]how to tell if your iac valve is going bad - YouTube[/ame]

 

[Grkstang]

Yea...i have to check itout .... might as well replace it its only $70 bucks for the motocraft

 

[NYSkinsfan]

I would take a shot at just cleaning your throttle body first to see if it helps out.

 

[Grkstang]

Im planning to clean the MAf sensor and throttle body. The thing is it only drops the RPMs when i turn on the heat or AC or try to turn the wheels, which i think it puts load on the IAC. So it might be the IAC afterall. IF i dont use heat or A/C RPMs are fine at 800 steady.

As of now plan of action.

1. Clean MAf sensor and throttle body
2. Replace IAC

should get the job done eventualy.

 

[lil' hellion]

some old tricks are the best u can try a can of penetrating oil spray anuond ur intake and when the rpm drops check that area for vaccum leak

 

[onlycodered]

Im planning to clean the MAf sensor and throttle body. The thing is it only drops the RPMs when i turn on the heat or AC or try to turn the wheels, which i think it puts load on the IAC. So it might be the IAC afterall. IF i dont use heat or A/C RPMs are fine at 800 steady.

As of now plan of action.

1. Clean MAf sensor and throttle body
2. Replace IAC

should get the job done eventualy.

Let us know if that does it. Good luck and hopefully that does the trick!