I just got my injectors back from cleaning at witchhunter.com and the
test pre-cleaning test results were pretty bad -- one injector was
only delivering 80% as much fuel, another only 90% as the other
two.   After cleaning they are all within 2%.    I haven't put them
back in yet to see if my rough idle and pinging under load are fixed,
but right now I'm wiling to blame all the van's problems on those
injectors.    I'll report back after reality collides with my
fantasies :)