Rep Power: 0

I have a 2001 Honda Civic LX ,(90,000 miles), that started idling rough a few months ago when I first started the engine. At first it only happened occaisionally and now it happens with each cold engine start. After the engine warms up it goes away and even restarting the engine when it is still warm does not produce the rough idle. I have tried several things without success. I started with a gas additive. I then replaced the spark plugs. I have unhooked the positive cable to reset the computer. I have removed the throttle body and cleaned it thoroughly. I have removed and cleaned the IAC valve. I have looked for vacuum leaks. Since cleaning the TB and IACV, I have also noticed that now I sometimes have an erratic idle that goes away when I give it some gas. I don't have a check engine light and the gas mileage has not been affected. So far nothing has really helped. Does anyone have any suggestions?

Thanks!

 
Rep Power: 0

im not sure on the rough idle it may be your timing but when you cleaned the TB did u replace the gasket?

 
Rep Power: 812

sounds like a small headgasket leak letting coolant into the engine and then the car has trouble starting when cold. once the coolant burns off, the car runs and starts fine when warm. are you losing any coolant? do the plugs have white deposits on em?

 
Rep Power: 0

I used a new gasket after cleaning the TB. I'm not losing any coolant. The old plugs didn't have white deposits on them. . .

 
Rep Power: 0

Hey,
I'm having a problem similar to yours, but my check engine light came on. The other week my 1998 civic lx with 175k miles started rough idle when cold start up but only lasted for about 5-10 seconds and it's usually rough on the second start up (warm or cold) but after that it's fine. The CE said its "cylinder 1 misfire". I've changed the spark plugs and wires.
Also about a year ago the radiator had a bad leak in it and I put a new in. Whenever it's hot outside drinks coolant like crazy and starts to over heat. Whenever I pulled out the old spark plugs and they were a white color on the tip, could this be a headgasket leak?
Thanks

 
Rep Power: 812

almost positive its headgasket leak and coolant is seeping into cylinders. white on plug is burnt coolant. if you dont have a visible leak and coolant is disappearing, its headgasket (burning coolant in the engine). i had the same problem and it would only misfire on cold starts for about 10 secs then everything ran fine.

 
Rep Power: 0

Thanks for the answer.
Do you think I can get away with buying that headgasket leak fix from autozone or should i have someone fix it? I can't do any extensive work becuase I'm away at college with no tools. :/
Thanks tons.

 
Rep Power: 314

The head gasket is not the Idle Air Control gasket. It is the gasket that is inbetween your engine head and your engine block. It is much larger than the new one that you used, and much more work to get it out. Sorry I gathered by your post that you were not 100% sure what a head gasket was.

 
Rep Power: 812

do not use any of those bottle repair fixes, it will only make things worse.

 
Rep Power: 314

Yea, only use those bottle repair fixes if you really hate your car

 
Rep Power: 0

alrighty, thanks for the advice. I took the honda to a radiator shop and they checked it and the mixture changed within 3 seconds and they said that was really bad. but i guess i'll get it fixed next week, honda (which is the second cheapest quote i've got) was around 1100-1200.
thanks for all the replys.

 
Rep Power: 0

I cleaned the air intake temp sensor using and dremmel tool to lightly scrap off the carbon buildup.

It worked for my car...Honda Civic 1989 LX.

Previously, I had purchased 2 new air intake temp sensors but I had the same problem.

I think this problem will be solved differently for every car, and I cannot guarantee it will fix your car problem.