surging idle on 95ex not caused by coolant bubble?

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voxleo

New Member
Hey y'all, I could use some help as I am having a frustrating issue with my 95 civic ex coupe: recently had thought that my surging idle woes were gone after I replaced my radiator thermostat and o2 sensor n did a whole flush/fill/bleed of the coolant. My CEL was giving me a primary o2 heater circuit code that went away immediately after that whole thing was done, and the idle surge went away for a while. It seemed to do it only when the car was cold at first, but had gotten worse before the maintenance above. This was just a couple months ago and I don't drive much - only a couple days a week sometimes.

Now the idle surge is back. It jogs between about 1000 and 1500 RPMs usually coming shortly after I start the car, but not immediately, maybe after I drive a half a block or so, and doesn't go away when it gets warmed up. It doesn't APPEAR to be a bubble in the coolant system since I've tried bleeding it several times now. Although I did notice that the coolant was low in the reservoir once after the radiator replacement, the level doesn't appear to have dropped again since then.

At one point after I had done the radiator/thermostat/o2 sensor change I got a single CEL that was either 22 or 21 (can't remember which - only that it was vtec related) but that went away on the next start and hasn't returned at all, so I thought it might be due to the weather we had, which was rather extreme cold or hot (can't remember which). But I am not getting any CEL now despite the surging idle problem.

Other than that, it appears to be running well - passed CA smog with flying colors. No power issues or anything, just the idle going wonky in Neutral at stops and such. (It's a manual 5 spd transmission)

Any ideas what could be the issue? What should I do next to troubleshoot?

I should mention I know f***all about cars. I'm a little 5'3 chick who is good at following instructions and handy enough to pull off some decent mechanical work as long as the instructions are good. So pictures and diagrams indicating what part is what when advising is especially appreciated, or at least what section to look it up in the service manuals (of which I have several).

Can't afford a new one just yet, so she is gonna have to go a little bit further , so thanks for any info or clues you can give me towards solving this.

It's bumming me out to have my victory over the last problem so short lived. But I guess it could be worse considering the car is 17 years old. I've had it since there were only 35 miles on her and literally drove it until the wheels (or rather ONE wheel) fell off of it, and I even have a youtube video of that part! http://www.youtube.com/watch?v=meL94si2qL0
 
Usually when you end up with a surging idle after warm up, you're looking at 3 specific items:

TPS Sensor
Idle Air Control Valve
MAP Sensor

Unfortunately I'm not intimately familiar with what the correct ways to test those specific components, however a repair manual will usually have the check list for each item in it.

You might be lucky enough to have someone post up the process of testing each item, however, a chilton manual or the more expensive helms manuals would be the way to find the answer for yourself. Personal opinion is to stay away from haynes manuals as they usually skip very important steps, and lack a lot of testing procedures.

Code 21/22 are either a bad vtec solenoid, or low oil...every time i've seen it, it's been right before my 3k mark for an oil change. Change the oil, and I'm good for another 3k.
 
ok remove your intake tube. look on throttle body near firewall on the inside while car is running.
should see two holes. put finger over the top hole. if car idles fine after it is your idle air valve.. if not cover bottom hole. if idles fine after that then it is your fitv. if that does not fix it cover both holes. if your car does not die then you have a vacuum leak... if it does you have a coolant problem.
 
i had the same probllem with my 95 del sol, i took mine apart it had a lot of gunk in it. Cleaned it up and runs like a champ.
 
im having a bit of the same problem with mine as well in a 92 lx sedan (sorry not trying to steal the thread just trying not to have to start a new thread)the car runs fine till warmed up and driven for awhile and ive already replaced the tps, fitv, and the iacv. all sensors have been cleaned and adjusted and even topped off the coolant afterwards. my only other option right now would be the map sensor but it seems to be working fine (better actually without the tps plugged in) any opinions?
 
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