1993 Saturn SC2 Car won't start in the heat

The car has had intermittent electrical problems in the past, supposedly due to cracked wiring which is now fixed. I drove it for awhile with no problems, after doing about 10hrs of driving in a couple day period, it started acting strange. RPM's would suddenly drop to 0 while driving, and "flicker" to normal and off a handful of times in a few seconds. Usually remedied by just taking foot off the pedal, and easing back into gas, although sometimes it would lose power.

Also now, it commonly won't start (it's been very warm here), but will sometimes start only one or two times when it's cool, then won't start again for hours. But when it does start, it runs rather normal until I turn it off, then I can expect it not to start for at least a few hours.

Any ideas? I'm by no means a car guy. So far someone expected it to be a Fuel Pump Modulator, which by the way he describes it, sounds reasonable, if that's the case, any info on how to replace this?
Thanks