Hi all, I 'm new here and sort of a newbie so I am looking for a little advice. I just picked up a 92 740 wagon which had a surging idle issue when I bought it. I went ahead and replaced a bunch of items including timing belt/roller, water pump, thermostat, intake manifold gasket, pcv and flame trap, all 3 belts and replaced a couple vacuum lines. Also cleaned the idle control and fuel pressure regulator. I wasn't sure if any of this had anything to do with the surge issue, but after I got everything back together and started it up it is still there. What is happening is when I start the car, any temperature and at any time ( even after just running right before) the enigine surge idles for anywhere between 30 seconds to well after a minute or 2. After this time, it smooths out and idles at around 750/800. It also drives normal without any issues. At this point it is more of an annoyance, but would like to get this corrected if I could. Also don't know if this is indicating an underlying bigger issue or something that could progressively get worst. Thanks is advance

 

First thing I'd do is check for intake air leaks. vacuum hoses, boots, seals etc. Not sure if your model has an idle air valve or not but if it does, you can clean it with carb cleaner to see if that helps.

 

this, from Dave Barton's website, might help
https://www.240turbo.com/vac-B230-EGRmed.jpg

 

Thanks for the feedback. I’ll check this weekend

 

moethshmoe just posted a cheap vacuum leak tester video he found using a harbor freight transfer pump and cheap cigars

 

Here ya go https://volvoforums.com/forum/volvo-...t-help-117204/

 

Hey appreciate the input… I cleaned the throttle body which was filthy and it went away for a bit but slowly came back. I am going to watch this video and give it a whirl. Thanks again