I have a 2001 Mitsubishi Galant ES with 99k. It is in good condition but I drove about 5-10 miles an hour over a speed bump the other day and all of the lights on the dash lite up and I could tell that the engine wasn't running right so I pulled over and put the vehicle in park and turned off the engine. I waited a few minutes to turn it back on and the lights, AC, Radio etc came on but it wouldn't turn over. I tried several times still no luck. The battery is new but we gave it a jump anyway still no luck. Fuses were fine and no loose wires so I towed it to a repair shop.
They informed me that the engine mounted sensor that communicates the engine information went out and isn't communicating with the computer. They informed me that it will cost $670 in parts and Labor to repair since it is mounted underneath the engine.

This is a lot of money to me (that I don't have) and a friend told me that it doesn't sound right. I already paid $50 for the tow and $175 for the diagnostic and really don't know where to go for a 2nd opinion.....any help or advice would be grealy appreciated :)

Thank you so much for reading and in advance for any helpful advice

Wow, $175 seems steep for a diagnosis on that sort of thing. I'm really not sure what that may be whether its a loose connection somewhere or what. If I were you I would take this into a mechanical problem solving forum (not the real name for it) part on AF. Good luck.