1994 Accord. Engine surging

94 Accord 2.0i. Engine is surging between 1000rpm and 2000rpm when stationary or the clutch is dipped when driving. Engine light has not come on and there appear to be no fault codes present. Otherwise, the
car drives perfectly ok.
Any suggestions? Failing lambda sensor perhaps?
Please help....this is the mother in law's car and it would make my life much more peaceful as well as earning major brownie points with the wife!!
Matt *** Free account sponsored by SecureIX.com *** *** Encrypt your Internet usage with a free VPN account from http://www.SecureIX.com ***
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Check the coolant level in the radiator with the engine cold. If it is low the sensors drive the ECU nuts and the idle hunts. If the level is low, you have a leak hunt ahead of you. The radiator is probably like the one in my daughter's '93; it has a flat spot on top where a brace crosses. Look for a crosswise hairline crack there where the flat spot flexes.
Mike
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Mike,
Does this particular model also use an Idle Air Control Valve? Can a bad IACV also produce this same type of idle surge?
Ron M.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I am pretty sure it does, though it may be called an EAC valve on this model.

I agree that's possible.
I concur with Mike's suggestion. In the same vein, do an air purge of the cooling system; a thorough one, where the radiator fan comes on twice (which may take 45 minutes of idling, so be patient).
Also, the oxygen sensor is suspect, too, particularly if the problem only occurs after the car is warmed up.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I had an earlier model Integra with a bad airflow regulator and it would display similar results, though it mainly happened when the engine was cold. The valve contained a "thermo-wax plunger" which had become deffective, resulting in differences of airflow into the injectors (or that's how it was described at least). As opposed to slowly closing proportional to engine temperature, it was erradic.
.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.