How do you know it's injectors not firing correctly ?

If you observed the spray pattern on each one ....ok.
but the test you describe is the same as pulling one spark plug wire at a
time...
you can tell which cylinders are running more strongly and which ones
weakly...

but, you don't actually know if it's misfiring spark plug, intake leak on
that cylinder, or injector issue.

I strongly recommend you never put premium fuel in your vanagon.
if you think you need higher octane ...use mid-grade.
otherwise use unleaded regular.....period.

fuel injector cleaner additives are fine..
I normally treat 'new used' vanagons with Lucas fuel injector cleaner .

with the information given...
if that's the only test you've done..
you are not up to being sure the injectors are not working right.
You need to see them spray before you can say that.
Typically if I go through a dozen used injectors, I can find 4 with pretty
nice spray patterns, in other words ....they do get old and worn and don't
work that perfectly after a while.

I'm sure 4 brand new ones would be nice ..
but see the old ones spray first.

Did you empty out the old fuel  filter backwards to see what's in it ..
like water, rust, dirt, or tiny shinny metal parts ?
Very important to do. ..provides very useful information sometimes.

I find 'most' vanagons having no contact at the idle switch at idle.  A
very, very common thing that gets out of whack and is often overlooked. I
also find too advanced timing a lot too.

for actually helping people who post..
it's very helpful if they say what engine or year van they are talking
about.
of course EFI injectors are injectors ...whether 1.9 or 2.1 ..
but ...
seldom do I ever find a vanagon with running , starting , or idling issues
and 'all' adjustments and components are perfectly working and adjusted, and
there is just one thing..
like injectors , that are faulty.

Almost *always* it's about 5 things half not right ...and maybe on thing
fully not right.
but it is almost never 'just one thing' .
Really ..
I've seen vans after people spent 600+ dollars at fancy shops ..
and the thing still wasn't right ..
in a few minutes I'm seeing this isn't adjusted right ..
this was left off, this was xyz 'not right' ...etc.   Air leaks, exhaust
leaks ..etc..
it all adds up.
one van was ..and he had spent a ton of $ too..
I did 3 things to it..
fixed the too advanced timing, the not-contacting throttle switch ..
and fixed an exhaust leak upstream of the O2 sensor ..
he didn't think it was going to be fixed ( loosing power ) ...but it was.
with just simple fixes too.

It's not in the parts..it's in the workmanship."
or workmanship and proper diagnosis.

Scott
www.turbovans.com

----- Original Message -----
From: "Brian T." <nobleman1962@YAHOO.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Sunday, December 05, 2010 2:39 PM
Subject: Scrambling for an answer ~ bear with me didnt search archives...
sticky injector issues

Well Jeez... my van sat for 6 days while I was on vacation and now the
injectors are not firing right. I just dumped some berryman in the tank and
filled it with super (chevron)

It has new plugs, cap, rotor, fuel filter and all connectors look good ~
popped each injector harness off and found one specifically that isn't
firing and another that is hit/miss.

Besides the fuel cleaning what can do to free these up? I just spent my $$$
on the vacation I'm returning from and don't have $600.00 for new injectors.

Thanks,
Brian