16F876A, I have a 1500 uf cap in front of an AP1084 5v regulator. On the 5v side, I have a 470uf cap. There are 24 1/4hp motors on the 12v side. They create alot noise so thats why I run the large value caps. Here is the deal, on power-up, quite often a PIC doesn't start. I couldn't figure out what was going on. Then I thought I needed to reprogram PIC, as soon as I connected the programmer, the PIC started. The next time it happened, I thought I would trace things out with my scope. As soon as I touch the scope lead to the MCLR pin, the PIC started again. Once it starts, it will keep going. I would say 75% of the time, I need to jump start with my scope.

Any ideas? What is happening to MCLR when I touch it with my scope? Maybe a cap on the MCLR line?
Thanks
Toby