Hey guys, I'm having problems with my sierra stopping suddenly while driving (not fun on busy roads >.<) but then starting again fine after 5-10 minutes, until last time I drove it when I left it parked and then found it wouldn't start again at all. So the RAC guy said it was something to do with the distributor/modulator and it started again but he said it wasn't fixed and would probably do the same thing again anytime.
I called some places about getting another 2nd hand dizzy and got quoted about $200, and told that they sell a lot of distributors for sierras because they have a common problem of the modulator (?) over heating.
So, I'm just wondering if anyone else has also had this problem, or has any ideas about what else it could be? My mechanical knowledge is pretty much zero

so I'd really appreciate any feedback or advice on this. Sorry there's already a related post, but I couldn't find one.