Engine Missing on Idle, 1998 S70 GLT

FritzMissel · Post by **FritzMissel** » 27 Feb 2008, 06:20

My 98 S70 GLT has 180K well maintained miles and still runs smoothly...except when at idle, and then only when there is slight load on the engine (ie in drive, reverse, or with AC running). I've checked/replaced plugs, and checked over the vacuum hoses. I found two breaks in the hoses and fixed them...same problem is occurring. Any ideas? Thanks!

farupp · Post by **farupp** » 27 Feb 2008, 07:03

Take a look at the "99S70 has a hard miss sometimes" thread a few posts down from yours.

darrengbsn · Post by **darrengbsn** » 04 Apr 2008, 16:36

I was having exactly the same problem you were (are). I checked vacuum hoses and changed plugs as you did - no help, I also replaced the MAF. Then I found that the 3-way hose which come directly out of the throttle body/intake manifold had rotted on the bottom - it was absolute luck that I found it. I was actually able even out the idle simply by crimping the hose with my hand, so I was pretty sure that I had found the culprit. Sure enough, after I replaced the hose my engine idles smoothly and my check engine light has not reappeared. Another member had the same problem and describes it better at:

https://www.matthewsvolvosite.com/chat/p ... hp?t=14353

here's a diagram: http://www.fcpgroton.com/product-exec/p ... ory_id/216

Good luck, Darren

1998 S70 GLT 130,000