I have a 97 DX Civic (non-VTEC) and I've got a very low idle, to the point where its starting to shake my shift knob violently. I'm fairly confident that it is a problem with the IACV needing to be adjusted, however my Haynes manual isn't helping in finding the damn thing. If anyone could provide me with some pictures/drawings/advice on finding this thing and adjusting it, that would be pretty sweet

 

it could be many things... from spark plugs, fuel filter, air filter, PCV valve... this last one is the most common cause for low idling... there is a screw on your throttle body... rotate it counterclockwise and it will allow more air in your engine... if this doesnt solve the problem.. try changing the stuff I told you...^^ anyways on your DX the IACV valve is light green and is located on the throttle body... it has 2 hoses attached to it...

 

the idle thing, hmm. now you got a good one. suddenly its a low idle. it once was normal for you i preceive and there was never a strange intermittant check engine light I would have to guess it is some kind of egr thing going on!?

 

a low idle on non vtec standards a low idle can be caused by a bad temp sensor i think.

 

I've been pretty consistent with changing all of those things with the PCV valve and fuel filter having been changed not more than 3-4000 miles ago. I changed the air filter this morning and not a noticeable change. This screw that you're talking about on my throttle body, do I need to remove the air filter housing to get to it?

 

if you have the stock air filter ....yes.. if u have an aftermarket intake it's very easy to get to...

 

Alright I adjusted the throttle screw today and all seems to be well, no more wild vibration and it seems to run just fine as well in normal driving. The obvious question at this point is whether or not this adjustment affects any of the various engine control systems in my car's montage of feedback loops. I wasn't aware that you could adjust the idle on a fuel-injected car, and I'm worried that I'll be screwing something up later on down the road...

 

i would wonder why suddenly you had to give it more air, the sideback is the map sensor will have a lower value possibly. also possibly you got goo in your iac.

 

yeah, from what i've heard the IACV does funny things to your idle when it's got gooy junk in it...mine idled at around 2k until it got warm, so i changed it out with a cleaner one and it droped down 500 rpm to a more comfortable idle...i would check your IACV...it's attached to the bottom of your throttle body...it's worth a shot, if it looks gummed up then just clean it out and slap it back on...good luck