The problem might not be the lifters.
I'd run a compression check before I took the heads off.
You could have something as simple as a sticking valve or just one lifter
that is intermittently failing.
You could also have a Fuel Injector that is stopped up or not firing
properly.
Clean the FI electrical connections.
Check the timing and your vacuum canister on your distributor.

Stan Wilder
Engine Ceramics
214-352-4931
www.engineceramics.com
----- Original Message -----
From: "Sam Johnson" <wrey45@YAHOO.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Thursday, April 14, 2005 2:39 PM
Subject: Hydraulic Valve Lifters!

> Hi all,
>        In addition to being very noisy when cold, can bad hydraulic valve
> lifters suddenly cause a serious loss of power while driving on the
freeway
> at 65 mph? They were pumped-up with no noise whatsoever when I left home,
> but once this happened, then they became very noisy and sometimes the van
> didn't even want to move from the stop sign (Embarassment!). Does this
mean
> the heads will have to come off? I have already tried Marvel Mystery Oil
and
> ATF in an attempt to make them quieter.
>
> Any help would be appreciated.
>
> Sam
>
>
> --
> No virus found in this incoming message.
> Checked by AVG Anti-Virus.
> Version: 7.0.308 / Virus Database: 266.9.10 - Release Date: 4/14/2005
>
>