Hi,
the exhaust of my 83.5 watercooled vanagon is pulsing and there is a
slight ticking sound.  hydrocarbons on one of the cylinders is way up,
but a new catalytic convertor let me pass SMOG.  However, I still want
to get my engine to run smoother.  I've taken the vehicle down to a VW
mechanic twice and they have not been able to identify the problem (not
sure if they tried too hard, even though I asked).

Here's what I've swapped out or adjusted trying to identify the problem:
  - all plug wires, brand new
  - new rotor and distributor cap
  - 4 fuel injectors
   - plugs
   - timing done by professional
   - valves adjusted twice by me and once by professional
   - checked compression twice myself and once by professional (all good
and balanced)

So, I'm thinking of the problem might be a bad hydraulic lifter.  Any
opinion on this?  I have not done a leak-down test and don't know how to
do it.  I do have a compression tester guage.

If people think it is the lifter, I'm willing to give it a go.  I can
take off the push-rod tube and put a collapsable tube back on.  However,
looking online, the Febi lifters are about $15 and a collapsable tube is
about the same.  So, I'm looking at about $30 a pop per tube and lifter
and there a 8.  It would be great to just spend the money on one tube
and lifter, instead of 8.

My 2 questions:
  1) do people think the problem I have is with the lifters?
  2) if so, how can I find out which lifter is bad?

Thanks.

Regards,
Craig