I have discovered a couple of dime sized rust holes in the frame on my '87 Toyota 4Runner. I've already had a friend cut some patch panels out of 1/8" steel that I intend to weld to the frame. I have good steel within an inch or less of the holes, so I'm not really worried about any substantial damage. (Although I will be keeping a closer eye on it). My question is whether or not grounding my mig welder to the frame will cause the computer any issues. I've heard that since the truck's computer also grounds to the frame, you can cause damage to it. I heard this a long time ago, so it may have been debunked by now. It's easy enough to pull the negative cable to shut the computer down, I just wondered if any of you had ever heard of this?

When I had my SFC's welded in, they said you just had to disconnect the battery, and the computer would be fine. If you have an aftermatket ignition (ie MSD) you have to disconnect it, however, because it can get screwed up.