[W126 Coupe] Slight miss-fire at idle

[mavris2 at comcast.net]

"I noticed that I have a fuel leak
around the o-rings on the altitude box that attaches to the fuel dist,
would that cause the misfire? Also I have bosch 4 platinum plugs in it,
should I switch them?

I had the same problem in my sel.  You have to replace the entire E.H.A. 
Valve
which comes with new O-ring, and two screws. Its very simply to change. 
Trust me getting new rings wont solve the problem. When they go bad the leak 
internaly.  Anyway, I too was runing +4.  Nope they were ok for a couple 
thousland miles then the slight miss started.  Switched back to oem plugs 
and new EHA and poof miss gone !

Jason

----- Original Message ----- 
From: "Pavel" <zhur0002 at umn.edu>
To: <mbcoupes at mbcoupes.com>
Sent: Thursday, March 02, 2006 3:33 PM
Subject: [W126 Coupe] Slight miss-fire at idle


> My 560 sel has been in storage for winter since last october.  I have
> started it for the first time yesterday to charge up the bat and let it
> clean itself out a little. It started good but has a slight missfire when
> in drive or just idling.  The car has just been overhauled completely 
> about
> 3k miles ago and I just had it running perfect before I put it away. It 
> has
> new injectors, euro heads, euro camshafts, euro exhaust manifolds, plug
> wires, dist rotor, distributor cap and a 3.47 rear end.
> Anyways when it first started it idled high about 1100rpm then after 30sec
> it would start to idle inconsistent would go from 1100rpm to 700 rpm and
> back up to 1100rpm.  It did that for about 10 minutes and then it leveled
> out at 700rpm with a slight missfire every few seconds(almost seems like a
> vacuum leak but I could not spot one).  I noticed that I have a fuel leak
> around the o-rings on the altitude box that attaches to the fuel dist,
> would that cause the missfire?  Also I have bosch 4 platinum plugs in it,
> should I switch them?  It ran fine with them before.
> Another strange thing it was doing was, if you rew it up and let of the 
> gas
> quickly it rews down and than stops at 1000rpm for about 10seconds and 
> then
> goes to 700rpm.
>
> PS.  I aslo stabilized the full tank of fuel in it before i put it away. 
> So
> I'm sure it has good gas. Again it is very slight misfire, but when you 
> sit
> inside the car you can feel the engine running, and that is making me very
> irritated.
> Pavel
>
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