hesitation / bog down

[hayes myers]

Sounds lke i should have a Mityvac. .. I don't think i hae a bypass valve
but could check. (turns out there was a cut-in on MC2 midstream of 91 which
may make this tricker to figure out.)I did buy a bypass valve (ala Ben
Swann) but haven't hooked it up yet...could be that it is time. I was
thinking maybe clogged injectors (had run couple of tanks with injector
cleaner in the mix)..or perhaps a dying fuel pump.  I'll see if i can't
follow the checks you indicate below and see what's what.  So begins the
deeper learning of CIS methinks.

Thanks Brett!
Hayes

On Fri, Dec 11, 2009 at 2:36 PM, Brett Dikeman <brett.dikeman at gmail.com>wrote:

> On Fri, Dec 11, 2009 at 1:41 PM, hayes myers <hayesmyers at gmail.com> wrote:
>
> >  let off and revs fall off like it's going to die.
>
> Classic signs of bypass valve failure, at least on the 20v's; the dead
> giveaway is when the report is of the engine idle dipping or engine
> dying coming off a freeway exit ramp.  It's almost always the cause
> for that exact symptom.  Don't the late 10v MC2s have bypass valves
> too?
>
> If you've got a mityvac, disconnect the control line from the intake
> manifold and apply vacuum.  The problem can be either the control line
> cracking, or the valve diaphragm tearing.  It's a $50-ish part, so
> definitely test before you replace.
>
> If the valve is fine (or you don't have one)- maybe check that the
> metering plate moves smoothly?
>
> Oh, also, is the ISV clean and working smoothly?  If it's gummed up,
> it can stick in a position where it is almost completely closed.
>
> Brett
>