Okay so im having a couple problems with my civic now. I turned the car on the other day and its fine for about 20 seconds until it warms up then it idles extremely rough and the longer it idles the closer it gets to stalling out. The engine shakes when its idling, it never did this before. The check engine light doesn't come on right away, it turns on when it starts to idle rough. I tried using a paper clip to check the error code but since the light doesnt come on right away it doesn't work. So i cant what the code is to figure out why its doing this.

I read it could be the fast idle control valve, or there is air in the coolant system but i wanted to get others inputs before i start fiddling with it for hours just for it to be the same.

Im not sure if any of these could be the cause but i think it would help if i said them. The battery is close to dead, the spark plug wires have been unplugged for about a month (when i plugged them in the car started first try), gas tank is full, oil change and coolant change recently.

Thank you

 

Codes are supposed to be remembered in ECU memory even after the key is turned off. If that doesn't work, check the "BACK UP" fuse under the hood. You can also pull over while the CEL is on-- don't turn the key off-- and put the paper clip in and it should blink the code.

 

It could be a whole host of things - you need to see what the CEL is coming on for. Does the engine "clean up" as revs increase, or does it feel rough the whole time you drive it?

 

Thats the hard part its not registered yet. When its parked and i rev it, it cleans up but then it goes right back to almsot stalling out.

 

When i get time im gonna try it and ill let you know what i get

 

The paper clip still isnt working but I figured out its running rich with gas. Im assuming a plug or wire doesnt have a good connection or came loose while working in it

 

Just my .02, but I did not have much luck with the paper clip and instead used a stripped section of single stranded telephone wire I had in my basement... Whether the light is on at the moment or off, the codes are stored in the ECU as mk378 mentioned; then just count the blinks.