So recently I noticed that as I go down hill and I wasn't accelerating my car would slightly jerk back and forth. Not much, but noticeable. Then it started to happen while idling in park and eventually idling in drive. It's weird because it's not like a normal idle problem that is erratic but it is quite....well not erratic but not normal. It goes in and out very methodically. I figured the best way would be to allow you guys to hear what it sounds like so I posted a YouTube video.
The link is http://www.youtube.com/watch?v=HBrQ6VgM16A. As you can hear, it's very consistent in the way it goes in and out. It hasn't caused the car to die but I am concerned it may get to that point. Today I went outside to video it and it didn't happen right away. I decided to kick on the AC and see if that started it...it didn't. It wasn't until I turned the AC off that it began to immediately do it. In any case I am at a loss. Any help would be greatly appreciated. Can't afford to lose our only family car.
One last thing, not sure if this is relevant. My VSS (speed sensor) went out some time ago. I have been driving without out it for awhile not (several months). I was a bit concerned this could be associated so I got a new one and while my speedometer is again working the problem with the idle is still there. As I thought about it more and the fact the VSS is attached to the trany which is obviously not working in park, I doubted more they are related. Not sure it that's correct or not.

Thanks

 

try cleaning the iacv........and might have air in the coolant system or a vacuum leak ,..........got any cel codes??

 

Don't have the ability to read codes, should get the device though. I did take your advice about the iacv and found another post that talked about how to clean it. Mine was really dirty. It seems like the problem is fixed. One question. Is it normal for the lines from the radiator to not leak any coolant when I took them off?

 

Idle surge can be related to VSS issues, but since you swapped in a new one I'm doubting that this is the case. Just to make sure, did you reset the ECU after swapping in the new VSS?

Your problem sounds a lot like the one I had after swapping a z6 into my 99 ex. Humor me and try this... With the engine cold, start it up. Let it sit and warm up completely on it's own, without touching any a/c buttons or anything. If the idle starts surging at or near when the car reaches normal Operating Temperature, you'll need to check out your Thermostat and try bleeding your coolant.

Coolant doesn't start flowing until the motor reaches normal operating temp, and the tstat opens up. If it's at that point when the idle begins to surge, you'll know where to start your fix-it process.

As for your coolant line question... Do the Radiator or the overflow bottle have any coolant in them? If so, you may want to try bleeding the coolant system. I do see that you have a bleed screw which makes the process quite simple. Here is a link to the DIY:

https://www.hondacivicforum.com/foru...=Bleed+Coolant

Good luck, let us know how things go.

 

With engine cold, take off the radiator cap. The radiator must stay full to the top. Don't count on just checking the level in the bottle.

 

About the VSS: I didn't reset the ECU. I've read about that in the past and am pretty sure I can find a past thread on how to do that. Is it pretty important? I understand it gets rid of any unnecessary lights on the dashboard, but will the car not run normally if this is not performed after changing the VSS?

About the idling problem: Problem seems to be solved. I ran the vehicle as you suggest Forty04 and it reached normal operating temperature and beyond and no problems. I guess cleaning the IACV did the trick. Thanks everyone.

Additional Problem: In addition the above issues my coolant gauge went from being too low, to near the bottom of the gauge to not working. It has been this way for awhile. I decided after reading around that I probably need a Coolant Sender Gauge. I've read this is the sensor near the distributor with one wire coming off it. I've looked around pretty good and cant seem to find it. I have thrown up some pictures of the inside of my car below. If anyone can point out where it is that would be a huge help.

Last thing. So I have no real clue of where my temp is at but in the past it was never an issue so hence the reason I lagged on getting a new sender. Thing is that recently I've noticed some cases where the radiator seems to bubbling into the overflow. I know this could mean a bleed is necessary. It also could mean the vehicle is too hot. Because of this I decided to let the car run extra long (over 20 minutes) at idle and wait for the fan to come on. I even ran the AC for a bit to heat up the system. It never kicked on. I am beginging to wonder if the coolant switch (turns fan off and on) is now bad also. Here's my question. Did I let the car run long enough to determine whether the fan should come on?

 

It's been a long time since I've done it, but there is a test to make sure the fan is functional and the switch is activating it. IIRC, you pull the connector off of the thermostat (the Coolant Temp Sensor connector, connected to the gold sensor) and bridge it's connections with a paper clip. With the car running, and connections bridged, the fan should turn on.

Again, all of this is from distant memory and I'm running on a minimal amount of coffee

Resetting the ECU is always a good idea after any electrical related upgrade or fix.

 

You should mention what year/engine/trim Civic you have.

For 92-00 Civics, remove the 7.5A hood Back Up fuse for a few minutes to reset the ECU.

 

Forty is right about the fan test. Unplug the switch on the thermostat housing (engine end of the lower radiator hose) and jumper the pins in the plug. The fan should then run constantly all the time the key is on regardless of temperature.

The sender is very hard to see with the distributor in place. You can take the distributor off-- mark its position, unscrew the 3 bolts, pull away from engine, no need to disconnect any wires. Then it's real obvious. If you unplug the wire and ground it, then turn the key on, the gauge should go all the way to hot. This tests the wiring and gauge so you can be sure the problem is the sender.

 

Thanks for the help. Oh, and I have a 93 DX. Last night I was able to find the Coolant Temperature Sender. I grounded the lead and sure enough the gauge went to the top. I also hunted for the Coolant Temperature Switch because the fan doesn't seem to be kicking on. I found it but couldn't seem to remove it. It felt from the underneath like it could require something to be pushed in before you could pull it out but that didn't work. I knew I took a risk of braking it off but I tried to wiggle the plastic part with a wrench........and......broken. So now I definitely need a switch as well. I did test the lead and the fan came on so I guess I needed it anyways.
I was reading through some other threads and they were talking about similar problems and how they could be related to low coolant levels. I mentioned before about how my car has been bubbling and I had to add water recently. I am wondering if perhaps there was insufficient coolant level and hence the reason both sensors were not working. Any thoughts on this idea?

P.S. What size socket is required to remove the Coolant Temperature Switch. It looks fairly large.