Ok guys, I have a '94 civic dx w/ 175,xxx & i picked it up w/ 148,xxx about 2 years ago & everything has been good till now. Just recently within the past two weeks or so the car has started to idle low. When i start the car up when it is cold it will idle low & lumpy/rough for about 5-10 seconds also when it is sitting at a stop light it idles the same way & almost feels like it is going to stall. So far i have changed the oil, put brand new plugs & wires in, checked the IACV which was real clean, and also replaced the thermostat & bled the system to get the air out. I'm almost stumped....i was thinking about a cap & rotor kit next, maybe replacing the fuel filter, and I've read up about Seafoam that I'm going to put a 1/3 in the crankcase, 1/3 in the vacuum line off the power brake booster, & then a 1/3 in the tank right before my next oil change. Has anyone had similar problems as this or have any suggestions? I'm new 2 the forum & any help would be greatly appreciated. RONJ if your reading this could you please post cause it seems you have great insight/advice on civics. Thanks.

 

have you tried to simply adjust the throttle cable on the throttle body?

if its to loose simply adjust the 2 nuts to pull the cable tighter.... my old 94 was alittle loose when i first got the motor running.
doesnt take alot adjustment only a tweak in my case for it to idle smoothly

 

no i havent looked into that yet..didnt even think about it...would the cable actual slip over time to cause that? and would that even be the cause for it 2 idle rough when starting it up....it seems like it is getting slightly worse...the problem was every now & then but it is becoming more frequent. I'm not sure what else 2 do & it is stumping me as to what it can be. It's almost like it is missing when it is idling but yet runs fine when once i take off & at crusing speeds...any other suggestions?

 

Is the CEL ON? Have you looked for codes stored in the ECU? Sometimes a bad IACV won't throw a code and won't look dirty. Nonetheless, try the ideas below first if you don't have any codes.

As you mentioned in your first post, definitely pull off the distributor cap and rotor and replace them, especially if you see any wear or corrosion at the contact points.

Have you tried to adjust the idle screw on the throttle body?

Have you checked whether the PCV valve and hose, as well as the breather hose, are clogged.

I also like your idea about doing a Seafoam treatment.

Is the battery/charge light ON on the dash? Do the headlights brighten and dim at night?

 

The CEL light wasnt on & hasnt came on yet & i havent checked for stored codes on the ECU...i'll look into a cap & rotor next

I havent tried the idle screw on the throttle body yet

I'm not that good on cars but I know a little but where is the PCV valve & hose at? so i can see if those are clogged.

I'm gonna try seafoam here very shortly

The battery light hasnt came on the dash and the headlights dont brighten or dim either.

one last thing tho...if anyone has any ideas....like i said i changed the thermostat last sunday and added more coolant & bled the system but when I was coming home last night the car started to come up in temp. again. Thats why i changed the thermostat and I have no idea what could be causing this to happen again. Anyone got any ideas?!?!?

 

For bleeding, did you turn the heater to MAX heat, put the car on an incline with the front end higher than the rear, open the bleeder bolt, and idle the engine with radiator cap loose until the fan turned on twice?

 

Could have a coolant leak. Is there any left in the bottle? Check the level in the radiator with the engine cold. The radiator should be full to the top. If you have coolant in the bottle but not in the radiator, replace the radiator cap, and also check the hose from the radiator to the bottle for cracking, etc. that would cause air leaks.