RPM drop when A/C come on! - 2003-04 Mach 1 Registry Owners Club

MyMustang · 05-11-2011, 01:44 PM

Ive been having this slight problem for a little bit where when I turn my A/C on the RPMs drop 200 and then jump back up to where it was before (hair under 750). From what I understand the IAC is suppose to bump up the RPMs a bit when the A/C is turned on vs them dropping and then returning to normal. When Im done driving and I go to turn the car off I shut the A/C off and the RPMs dont jump up or anything they just dump down and return when turned on. Is this normal for most Machs. I have to mention I have a K&N CAI and have heard of idle and rpm issues with the CAI and no tune but nothing A/C related. Anyhelp is always appreciated. Forgot to mention that the IAC was replaced within last 3 month and MAF was cleaned with CnC MAf cleaner.

NastyNate · 05-11-2011, 01:59 PM

With my K&N the Rpms would stumble getting off the freeway. I put the Maf screen back in and it helped. You might want to try disconnecting the battery and letting the computer reset. Then let the car run so that it can re-learn everything. Let it idle with the A/c on so it will learn the parameters with the load on the engine.

MyMustang · 05-13-2011, 11:18 AM

Quote:

Originally Posted by NastyNate

With my K&N the Rpms would stumble getting off the freeway. I put the Maf screen back in and it helped. You might want to try disconnecting the battery and letting the computer reset. Then let the car run so that it can re-learn everything. Let it idle with the A/c on so it will learn the parameters with the load on the engine.

I have tried this and after I do it and turn the A/C on it seems to work properly but after a little driving it goes right back to how it was... I just started really using my A/C for the first time in a few months though dont know if that matters... Also I dont have the screen anymore any ideas on where to get one??

05-11-2011, 01:44 PM	#1
MyMustang Registered User Join Date: Oct 2010 Location: Jacksonville, FL Posts: 65	RPM drop when A/C come on! Ive been having this slight problem for a little bit where when I turn my A/C on the RPMs drop 200 and then jump back up to where it was before (hair under 750). From what I understand the IAC is suppose to bump up the RPMs a bit when the A/C is turned on vs them dropping and then returning to normal. When Im done driving and I go to turn the car off I shut the A/C off and the RPMs dont jump up or anything they just dump down and return when turned on. Is this normal for most Machs. I have to mention I have a K&N CAI and have heard of idle and rpm issues with the CAI and no tune but nothing A/C related. Anyhelp is always appreciated. Forgot to mention that the IAC was replaced within last 3 month and MAF was cleaned with CnC MAf cleaner. Last edited by MyMustang; 05-11-2011 at 04:20 PM. Reason: forgot to mention

05-11-2011, 01:59 PM	#2
NastyNate Registered User Join Date: Mar 2008 Location: Jersey Shore Posts: 1,349	Re: RPM drop when A/C come on! With my K&N the Rpms would stumble getting off the freeway. I put the Maf screen back in and it helped. You might want to try disconnecting the battery and letting the computer reset. Then let the car run so that it can re-learn everything. Let it idle with the A/c on so it will learn the parameters with the load on the engine.

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