I did some searching, but most of what I found was solutions for hunting idles on MPFI models. I do not have a hunting idle issue, and my car is DPFI.

The issue is, everything runs perfectly normal when the engine is fully warmed up, but from first start through the entire warm up process, pressing on the brake and coming to a stop causes the idle to lug way down briefly before jumping back up to the normal idle of 500rpm. If I am running the A/C, the same thing will happen except worse to where it will actually stall. Once the engine is fully hot though, the entire issue goes away.

Where do I begin to troubleshoot this?

 

500 rpm to too low of an idle. Idle should be around 800 rpm. Reset your idle and see if that works.

 

are you sure? I've had an 84 crx, 89 civic wagon, 91 civic wagon, and 90 crx and every one of them has always idled normally at exactly 500 on the tach.

Or maybe the tachs in these cars were just not very accurate at idle speeds?

 

500 is the idle speed when the IACV is disconnected.

 

it should idle at 750. the tach does not show less than 500. you might be reading it wrong.

as for your bogging, check your check valve or booster system. it might be sucking too much air when braking.

 

I had a similar issue on my car when I first got the AC working, it would never bog all the way down and stall, but it would run down so low it would idle very very rough and shake my car to death. I ended up just having to set the idle a bit high to compensate. My idle is now about 900 or so. Been that way for years now, a little high, but stops the annoying bog down at idle.

 

Ok so yes I've been reading the tach wrong, all my hondas have idled at 750. The brake and AC combo has been causing it to dip down to 500 or lower.

Will try some of the advice here and will post if I figure out the culprit.

 

Okay... so brake booster passed all tests, and removing and cleaning the IACV has not fixed the issue.

Is there anything else I should try before I get too tempted to mess with the idle set screw?