Larry Carlson says: "Robert Crumb did a feature about Philip Dick's "Valis" experience , published in Weirdo comic #17 from summer, 1986.
You will find all 8 pages of this story here. The file sizes are rather large (120-140K each) so that the text is readable and the detail visible." (Note: I highly recommend that you order Weirdo #17 from the publisher, Last Gasp. It's only $3.95. All 28 issues of Weirdo are terrific — it's where I first learned about The Church of the Subgenius and Stanislav Szukalski, too.)