[V8] Stumbling / surging problem

[Ed Kellock]

What about vacuum leaks?  Breather hoses, vacuum lines, etc.  

Ed

> -----Original Message-----
> From: v8-bounces at audifans.com 
> [mailto:v8-bounces at audifans.com] On Behalf Of cobram at juno.com
> Sent: Monday, July 24, 2006 11:00 PM
> To: david at styletrack401k.com
> Cc: v8 at audifans.com
> Subject: Re: [V8] Stumbling / surging problem
> 
> 
> You might want to check the engine reference sender(s).  
> After warmed up it might be closing a fault in the sensor or 
> the wire, when cold it might be throwing an intermittent 
> signal.  They usually fail in one shot (car just won't 
> start), or with the car hot (dies and have to wait for it to 
> cool a bit to get going again -hi Ed), but I have seen ONE 
> that was failing when cold. "Fairly new O2 sensor" would also 
> warrant a good check of the reference sender plugs. Also, 
> make sure that you've got the TPS adjusted correctly, it too 
> can cause your symptoms.
> 
> BCNU,
> http://www.geocities.com/cobramsri/
> Health is merely the slowest possible rate at which one can die.
>  
> "David Lyddall" <david at styletrack401k.com> writes:
> > Has anyone come across a problem like this one:
> > 
> >  
> > 
> > I have a black '90 V8q auto, and when it's cold, it drives like it
> > is
> > running out of gas.  It idles fine, but at partial throttle it 
> > really feels
> > like it's starving of fuel.  When it does this, you can 
> floor it and 
> > it will
> > get up and go, although it feels a little short on power.
> > 
> >  
> > 
> > Here's the list of things I've tried - I double checked that the
> > timing is
> > correct - it was off a couple of teeth on the cams, but it is fine 
> > now.  It
> > has a new fuel pump - the old one was wining like crazy, but that 
> > wasn't the
> > problem.
> > 
> >  
> > 
> > It feels like a bad mass air flow meter - bogging down under
> > partial
> > throttle, but I switched the one out of my other V8q and it made no
> > difference.  Also tried switching the TPS, but made no change 
> > either.
> > 
> >  
> > 
> > It has a fairly new oxygen sensor, so I think that is unlikely to be
> > the
> > problem.
> > 
> >  
> > 
> > Before I got the car it had sat for about 3 years, so the fuel
> > system was
> > full of varnish.  It does have a new fuel filter, but I wonder if 
> > maybe the
> > fuel pressure regulator is causing trouble.
> > 
> >  
> > 
> > Any ideas would be appreciated - I really would like to make this
> > car run
> > right.  I've been using it as a loaner car at my shop, and it gets 
> > old
> > explaining to people what they need to do when it dies on them.
> > 
> >  
> > 
> > Thanks
> > 
> >  
> > 
> > Dave
> > 
> >  
> > 
> > 90 v8q x2
> > 
> > 96 a6w
>  
>  
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