You should have a man go with you when you go to the mechanic. There are plenty of stories about shady automotive shops taking advantage of women that walk in.
As for the online diagnostics, could be a fuel filter, cheap fix, kinda messy. Could be plugs and wires. How many miles on the vehicle, and how long since last tune-up?
"Damn straight! Today the mad scientist can't get a doomsday device, tomorrow it's the mad grad student! Where will it end?!" - Professor Hubert Farnsworth