Up and down idle when weather is cold

Hello,

I'm hoping somebody can help shed some light on this problem. My
vehicle only does this as the weather gets cold. Throughout the summer
I don't have the problem. It only returns in cold weather.

When I first start my vehicle the engine will idle normal for a minute
or so then it will go into rev up then drop off then rev up loop over
and over. I found if I put the vehicle into gear the strange idle
stops. Also if left longs enough without putting it into gear for 10
or 15 minutes I believe it will correct itself and stop reving up and
down. However I've only witnessed this once as I generally don't wait
around long enough for it to stop. Like I said as soon as I drive it
goes away. By the time I get to where I'm going it will sit and idle
just fine?

Thank you for your time. Any responses will be greatly appreciated.

Thank you, Jeff

 

If you can identify the bleed screw, release the screw to force air out
once you fill coolant up to the filler neck on a warm motor with the heater
on Max. There are a couple sensor that can foul your 92 Accord cold idle.
The EACV is one of them.

 

-----------------------------

Cool, Psychic diagnosis. It does exist!! OP didn't mention the make,
year, or model, did they?

'Curly'

 

I'm sorry. The vehicle is a 91 Honda Accord EX.
I didn't quite understand the 2nd posting can anyone give some more
detail?

Thank you, Jeff

 

The suggestion is that you have an airlock in the cooling system that is
confusing the car's sensors and the EAVC. He/she suggests you bleed the
system to remove the trapped air.

 

Bleeding is important. I'd set up a page just for bleeding. Check it out here.

http://square.cjb.cc/c/?HowToBleedCoolants

I'd kinda knew the OP has a 91or 92 from his history. Anyway, most of the
fluctuating RPM tends to happen to fuel injected Hondas.