Okay, my girlfriend 99 Civic no mods and it has this problem. Randomly it will surge, it sounds like the car is going to die and then it starts idling low then normal low then normal. This happens only when you have the ac on I have noticed. In the middle of the surge if I turn off the ac everything smooths out. I thought it was Iacv at first but then found that it was only doing it while the ac was on. Anyone have any Ideas?

 

ttt

 

Well the IACV is supposed to regulate idle by allowing more air to enter the engine when you turn on the AC or there is some load on the engine. A bad IACV can cause problems when you turn on your AC. I've tried disconnecting my IACV before and then turned on my AC. The car's RPM dropped badly to the point where the car wanted to die. Since the IACV wasn't connected, it couldn't regulate the idle based on engine load.

 

you can also check the pressure sensor on the condensor..if that goes bad, more load on your engine will be applied which will cause the low idle when AC is on

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blk_eg4 &raquo;</TD></TR><TR><TD CLASS="quote">you can also check the pressure sensor on the condensor..if that goes bad, more load on your engine will be applied which will cause the low idle when AC is on</TD></TR></TABLE>

I thought the compressor's job is to cut-off if there are any pressure problems.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sageuvagony &raquo;</TD></TR><TR><TD CLASS="quote">
I thought the compressor's job is to cut-off if there are any pressure problems. </TD></TR></TABLE>

i had the same problem, and when the pressure switch was replaced the idle became normal...

 

You know, this whole time I thought the topic read "Compressor Surge" which had me thinking a different way... ahh!