Lugnut,
If you haven't already done so, replace the two fuel injection fuses (5 and 8 usually). I had a similar problem and both fuses looked good but after I replaced them the problem went away. The reason was that one of them had a harline crack across it. See Greg Gordon's L-Jet tune-up page (about 1/3 of the way down.)
Good Luck
Jeff
L-Jetronic