Date:         Fri, 15 Jul 94 16:52:58 CDT
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         Joel Walker <JWALKER@ua1vm.ua.edu>
Subject:      Re: Stumblin' and misfiren'

On Thu, 14 Jul 94 20:39:25 CDT Jim Macklow said:
>My sweet little '87 Syncro has the following peculiarity...
>Sometimes, when pushing down the accelerator, the engine hesitates
>and doesn't seem to be firing.  This behaviour is worse when rpms

check the tension on the accelerator cable. if it is too tight, it can
act funny.  but then, it shouldn't get better if it is the cable.
check the little microswitch on the throttle housing. if that thing is
mal-ajusted, it can make the engine thing the throttle is not completely
closed, and it will run funny.

>This problem seems to be worse when the ambient air temperature is
>"warm", that is, over 65 degrees.  I _never_ have the problem when
>I first start driving, although it will usually start within 30
>seconds or minute of driving.  Cold weather keeps this behavior away
>as well.

i'd almost bet on that idle air valve thingie, that is supposed to open
up as your engine gets warm. it's the thick rubber thing with an electrical
connection, kinda in the middle (but slightly to the right rear) of the
engine. it's supposed to 'hummm and vibrate' if it is in good shape.
(although i never have been able to tell if it is doing anything).

but! a quick cheap thing to check would be carbon deposits on the intake
valves. they can soak up the first bunch of gasoline sprayed on acceleration
and can cause driveability problems. get some Chevron Techron and try a
couple of bottles of that (or the vw stuff) and see if that helps. if it
does, then you need to have your valves de-carbonized. costs about $60 and
they do it without removing anything from the car (squirt some 'stuff' into
the manifold, and it dissolves the carbon).

i'll look through the tech bulletins and see if i can find anything else.
joel