I've done lots of searching reading various threads on this but it has been unclear if anyone has described the exact issue I'm experiencing. I am not a car person, btw, but I can at least look for things if anyone has any suggestions. I'll try to describe the issue as specifically as I can.

The problem is the idle sounds rough every 10 seconds or so with the a/c turned on. When you first start up the car, even after a minute, it's a little rough but not too bad. It may get progressively worse just sitting there, not sure. But after I start driving for a bit and then come to a stop, the idling roughness become obvious. When it occurs, the RPM's dip and then almost pulse like a wave for a few seconds before going back to normal. 10 seconds later it repeats. When I say "pulse", I don't meant drastically. It's still at a low sputtering RPM. There are some loud a/c exhalation type sounds when this happens. I think it's also happening while driving with the a/c on because sometimes I'll hit the gas and it might be sluggish a bit but then accelerate. Maybe because I'm pushing the gas more to make up for the sluggishness. The a/c works, but I THINK it may not be as effective as it normally is. I can't be too sure of that though because it's HOT outside. If I turn the a/c off I have ZERO issues.

My car has about 200k miles on it and I just had a ton of routine maintenance done to it by an experienced technician. It was having the issue prior to the work being done. It's probably not as bad as it was, but it's definitely not right. I can list some of things I had done if that would help rule some things out.

I would appreciate any suggestions.

 

It sounds like either the A/C system is overcharged with refrigerant or the condenser fan fails to run when the A/C is turned on.

 

Thanks for the quick response.

At what point could the A/C have been overcharged with refrigerant? I've had the car for a very long time and I don't think anything specifically has been done to the A/C. Are there other procedures done where the A/C might have become overcharged? I think I had a new radiator installed about 3 years ago, but I'm not sure that would be related. Also, this seems to be a fairly recent development.

Where can I view the condenser fan?

 

Overcharging could only occur by adding refrigerant to the system or during the course of work done to the system. Your answer seems to rule out this possibility.

There are two fans in the engine bay, the radiator fan on the passenger side and the condenser fan on the driver's side. The condenser fan should run when the A/C button is pressed with the engine idling. If it doesn't run, you found the problem.

 

Neat. I'll pray and have a look.

 

^of course, also with the cabin blower turned on

 

OK, I checked the condenser fan and it's definitely not consistently staying on. Does it matter if I'm in Park/Neutral/Drive as to whether or not the fan should blow? I don't need an in-depth answer, but how would this fan not coming on affect the idle being rough? I need to understand better.

 

The condenser fan should run anytime the compressor clutch is engaged. So if the fan turns off and the compressor clutch disengages at about the same time, then the fan is operating properly.

The fan cools the condenser. If the fan doesn't work, then the refrigerant pressure on the high side rises to abnormally high levels, which increases the load on the engine because the compressor needs to work harder. This will affect the idle speed.

 

Well, I think you solved my problem! The fan is not functioning properly. I don't know if it's bad connections or the fan itself, but that's good enough for me. I can hardly get it to come on at all at idle. I think I had to rev the engine and it ran for a little bit and stopped. Any idea how much it would cost if i went to the dealership, or is this something any shop should be able to fix very easily without f'ing my car up? I hate it that I just got back from my Honda guy doing the tune-up (he lives a good distance away) and am just now figuring this out. But thank you very very much. This has likely made my day, believe it or not.

 

No, but it's best to do the test with the engine in Park.