a/c making van idle rough?

My mother in-law has 2001 Villager. Well yesterday she went to leave and turned her a/c on and it started running real rough like it wanted to cut off. The service engine light came on. Well she called me and I told her to shut the a/c off and the service engine light went off and it ran fine. What could it be? Should I have her take it to autozone to see what codes it brings up?

Yes start with getting the codes, remember codes dont' mean part is bad the code just points you in the problem area.

WHich engine, I suspect the 3.3??

How many miles on vehicle?

Any history is helpful.

Thanks, when she gets the codes I'll post them

Without the codes I would clean the throttle body.

Well went to autozone, because it is a service engine soon light that comes on they can't pull a code. They told us to go to pep boys.... They want $90. Well my mother in-law I think was hoping someone at pep boys would know the problem because she can't afford the $90 to see what is wrong plus whatever it is going to cost to fix it. Her brother thinks it may be the a/c clutch going out? I have a Lincoln and mine has a fuse for the a/c clutch but the villager doesn't have one. Also when my fuse went out it blew nothing but hot air. So I'm not sure that is the problem. So any other info is greatly appreciated.

Look I don’t know exactly what you where told but, AutoZone will pull codes no matter what state the MIL is in. that is the hole point to get you in the door and then sell you parts.

They will not clear the codes. Just about every parts store that caters to john Q public will read the codes for you. And by the way you can buy an OBD II reader for around 50 $. AutoZone even sells an Acutron Universal code reader and clearer for about 60$. If what you say about Pepboys charging to read codes is true….. I am confident that I could stand in the parking lot making a darn good living charging 20$ to read codes. I have a CP9185 scanner reader that helps point to the problem far better than just a reader. I also have a air bag and a ABS scnner.


so well any who. is there any other time that your engine runs ruff? If your air bypass valve is bad, or the ECM is missing the A/C request signal it has no idea to kick up the idle and will come close to stalling

When was the last tune up done?

Clean Throttle body.

Clean MAF sensor.

Does it idle rough with a/c on cold or warm engine or both??

Clean IAC also.

Well back to the autozone thing. He said they couldn't pull codes unless the check engine light was on. They couldn't pull codes just for service engine soon light. He even hooked it up to try and nothing. Well she bought it in 2006 and hasn't had a tune up done (don't yell at me its not my vehicle). She has had the belts replaced and oil changes when due. I have a friend that is going to do what you suggested to see if that helps. Thanks for all the info!

Sorry forgot to say it idles rough cold and warmed up. And the miles on it is 82666

Hi, I have a similar problem with my villager. To be honest I don't think its worth putting any money into.

What seems to be happening is this, there is a problem with the AC system, that causes the AC compressor & fan to cycle on and off, the energy needed to get all that moving momentarily robs the motor of current ( bad spark @ the plugs). This causes a rough idle for a few moments, but seeing as the AC is constantly going on and off, it seems like the engine is always idling rough. I simply avoid using the AC, or use it only when the van is moving. Im having no problems.

Before spending money on anything else, Id have the AC looked @ first. I think whatever regulates the AC fan/compressor is bad

Well she took it in to the shop and come to find out she had a busted motor mount. Now its running fine and the a/c is working.

well Ill be...

Well she took it in to the shop and come to find out she had a busted motor mount. Now its running fine and the a/c is working.


Thanks for letting us know the fix. I do not quite understand how a motor mount can affect idle but glad it is working fine now.

EDIT:
The only thing I can think of that the connections to the FIC/IAC were moved during the motor mount repair which corrected a loose or bad connection.

Thanks for letting us know the fix. I do not quite understand how a motor mount can affect idle but glad it is working fine now.

EDIT:
The only thing I can think of that the connections to the FIC/IAC were moved during the motor mount repair which corrected a loose or bad connection.

My guess is, she confused the shake from the low idle and broken motor mount with a rough idle. It was probably running fine.