Guys you have to be comfortable with disassembly down to the individual head components but I posted a solution I found here
http://signs101.com/forums/showthread.php?p=857660#post857660
I will add that once you get down to the head only with the manifold removed, if you catch the light just right, on the adhesive plastic electrical connectors that go down into the head, you may see some lifting.
Pressing these back down with a piece of plastic, soft edged, running along all of the contacts fixed my error 07's
I know that this may sound esoteric, but when you see it you will appreciate what I'm explaining.
My theory is that the adhesive used detoriorates in sections and the contacts become unreliable for some of the data paths.
I have a permanent fix that I want to try which I'll document with pics, but am in the middle of moving house, so it will be a few weeks at best.