Perhaps the cold start valve needs a little cleaning?  Maybe replacement?

Just a thought.

----- Original Message -----
From: Larry L Meyer <llmeyer@juno.com>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Friday, July 28, 2000 12:57 PM
Subject: Hesitation & Slow Starts

> I have a 86 vanagon with 128,000 miles.  Just replaced the engine with a
> new rebuilt from Boston Engine.  Here's the problem:  When I first start
> it up after sitting overnight, everything is normal.  Idles at 800-1000
> rpm but "bucks" a bit until it has run for a minute or two.  After it has
> warmed up to normal operating temperature, it will idle at about 2000
> whenever I'm stopped at a red light.  Then when I take off from the
> light, it will hesitate and start very slowly as if it is starving for
> fuel until I get it up to about 2500 rpms.  After that it runs and sounds
> normal.  I have replaced the O2 sensor, re-checked the timing (its
> correct), and have replaced the distributor cap.  I also tested the idle
> speed control and it seems okay---vibrates like the Haynes manual says it
> should.  So, what do I check next?  Any suggestions from the list?
> Thanks in advance.
>
> Larry in Lincoln