surging idle when driving cold

[blackdemon88]

Hi Guys I have a problem I just can't figure out with my 1989 Honda Civic DX. I have tried everything I can think of and the problem still hasn't gone away! What is happening is when the car is started it idles fine but when I take it out to drive the Idle will sort of surge up and down when I start to slow down at a stop sign or light. The funny thing is it only does it when it is cold. Once it warms up and I stop at a sign or light it will idle normally. I have done everything I can think of to solve this problem to no avail! I've replaced plugs,wires,cap,rotor,air fiter,fuel filter,pcv,I have taken the IACV off and cleaned it but mine is sealed so I can't adjust the white high idle cam inside. I have replaced the TPS from another throttle body but when I set the voltage on it I set the idle at .50v but when I went to the full open throttle it would only go up to 3.92 volts instead of 4.5 volts like it is supposed to. I am sorry for the long post but I wanted to be thorough to you guys on what I've done. Any help you can give me would greatly be appreciated. Thankyou,Michael

 

[RonJ]

Clean the fast idle valve.

 

[blackdemon88]

Thank you for your reply RonJ. I'm sorry if this is a dumb question but where is the fast idle valve? Like I said I did clean the IACVvalve. Unless you are talking about something else???

 

[RonJ]

I forgot that the Si has the fast idle valve and the DX doesn't.

Try this:

 

[blackdemon88]

I have tried what you said and it did not seem to help at all. Could it be my temp. sensor or even my O2 sensor? I am not getting any codes but this problem is driving me nuts! Thankyou for your help so far. The funny thing is that it will idle cold fine-It is just when I drive it and the I let off the throttle when I am coming to a stop sign, that is when it seems to be "searching" for a idle. About the Temp. The gauge in the car reads just under half but it seems that once the fan comes on it doesn't shut off unless I turn the car off. Otherwise it always seems like it is always on once it warms up