The exhaust leak will cause the bad idle after it warms up. The O2 sensor
is not getting a real reading with the leak. The ECU doesn't pay attention
to the O2 until a certain temperature is reached when the engine is warmed
up.

Once you fix the leak, your idle problem will probably magically
disappear. ;)

Jon

On Fri, 1 Jun 2007, chris Moyles wrote:

> I just went through this process and had to grind off the bolt heads-
>
> FYI - I ordered a set of  exhaust manifolds one of our  list venders:
> it came  from S & S headers in three pieces -
> The front manifold  was one piece and the rear was two pieces with slip
> fittings...
> 4 hours and a lot of swearing later I got the thing on and together and
> it is just enough out of alignment that I've got a leak at the front
> left of the manifold port.
> Be warned, if you get one of these you might have to take it to be
> heated and bent to fit properly.  Also, there was not enough clearance
> for the rock shield/bottom engine
> mount to bolt properly back to the bottom of the engine.
>
> On top of that, now the van has an idling issue.  After it warms up for
> about 5 minutes it doesn't idle -
> So I day of troubleshooting ahead, could be anything from a clogged
> catalytic converter (already checked the O2 sensor), etc...
>
> Funny thing, the van was running like a champ before I decided to fix
> the exhaust leak...
>
> Such is life -
> and get a quality replacement part!
>
> chris
>
>
>  Marla Stelk wrote:
> > Hello listees,
> >
> > So I foolishly thought it would be a simple fix...
> > I have a leak in my exhaust where a manifold has either deteriorated
> > or blown out (the cause I'm thinking of my idling issues).  I bought a
> > new one to replace it thinking I could just undue the exhaust bolts,
> > slide the old one out and slide the new one in.  Of course, however,
> > my exhaust, although replaced about 4 years ago is all rusty now and
> > the bolts are basically parts of the pipes now.  Any tips on how I
> > should proceed?
> >
> > Thanks in advance,
> > MJ Stelk
> > '87 Westy GL
> >
> > ------------------------------------------------------------------------
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> > MSN <http://g.msn.com/8HMAENUS/2743??PS=47575>
>