I had an 87 S10 that had electrical problems for 2 years. I bought it new. I would have to unplug the alternator to drive it in the morning before it warmed up. Once it warmed up I could plug it back in and it would run, but not well. I replaced sensors, hooked up the $3K Snap on scanner, nothing. Replaced 3 alternators, ECU & PROM together(that helped for a month). Finally to appease the Mrs & the in-laws, I let it go to an electric shop. They had it for 3 days, gave them $75 when it was dropped off, then they told me there was an echo in the fuel circuit, and they "almost had it, we're close" but it would be another $225 for diagnosis only. I picked it up, they hacked up my harness, they put a butt connector less than an inch from the ECU connector, they left a razor blade on top of the radiator, and were no closer to fixing it than I was.
I eventually found it- it was the sensor(cam/crank sensor?) under the rotor button, above the ignition module. EVERY FLAPS in town wanted to sell me an ignition module when I tried to explain it to them. I eventually got a good one from the junk yard. I kinda wish I hadn't, because had that sensor not worked, I had a 301 turbo on the stand waiting for a home. That sensor was the last straw.
Bottom line- If it's going to a shop, find one that's got a SOLID reputation of being able to fix ANYTHING, not just someone with "Electric" in the name. If you don't have time to deal with it, that may be the best course to take.