A connection in the fuse box. One of the relay legs when pushed in had pushed the spade connection out the bottom so it was making contact but every so often it would loose that connection. Drove me nuts for years.
Yes I have done mine a while back. I had intermittent starting problems. Replaced battery; not that. The broke down at work. AA took one look at it and toed me to the dealer. Dealer fixed. Never gone since (touch wood).