Idle problems
Thread Starter
4th Gear
Joined: Aug 2005
Posts: 4
Likes: 0
Idle problems
Am new UK 85 corvette owner and am well happy with car other than an erratic idle from 400 rpm to 750 rpm. I have checked for vacum leaks, set up the idle as per manual but the problem still exists. With the IAC disconnected the idle is rock solid the minute it is plugged back in the idle becomes erratic again. Am i to presume the IAC is knackered or that it is functioning correctly but it is receiving incorrect information which it is responding to which then causes the erratic idle? As UK based not many other owners around or would just swop valves with one that i know is functioing correctly. The only other thing is could it be the AC as when i bought the car that was not functioning and all electrical connections have been disconnected. Any help would be greatly appreciated as parts are not exactly cheap over here and dont want to order parts that are not needed. 
Pro
Joined: Jul 2004
Posts: 639
Likes: 0
From: 1985 L98, Auto. O'FALLON, IL
Try to disconnect the O2 sensor after the car has warmed up, when I first got my 85 I had the same problem. Someone on the forum advised that I try that and when I disconnected it the problem was gone. I replaced it and it idle much better now. I think it was only 25$ at the local autozone. They also sell part on line so you could order one and have it mailed to you.
Racer
Joined: Jun 2005
Posts: 416
Likes: 0
From: Gansevoort NY
I a having the same problem with my 85 currently. I have set the base idle as described as well. And when I disconnect the IAC mine also idles flawlessly. 
I just so happen to have a O2 sensor sitting waiting to get put in this will be my next project.
I just so happen to have a O2 sensor sitting waiting to get put in this will be my next project.
Thread Starter
4th Gear
Joined: Aug 2005
Posts: 4
Likes: 0
Thanks will try the oxygen sensor over the weekend, hope i am that lucky and that is all it is. Have already cleaned all the inside of the throttle body and the IAC to rule that one out. Dont mind buying new sensor if thats all it is i think the reason it is bugging me so much is cause its an auto if the revs creep up to much it kinda of clunks as you go into drive and pull off if it decides to idle correctly it pulls off smoothly and silently. On the plus side if i have to mail order new sensor may order a few extras like modified air box, cooler running stat and any other easy to ship items that will make her go quicker. Ironic that i want it to quicker and use more fuel when every petrol station round here is now charging around £1:05 for a litre of standard unleaded, oh well dont travel that far so will live with it for now.
