2000 silhouette won't start

My car wouldn't start so finally had it towed. As soon as the mechanic tried it the engine fired and ran fine. Couldn't get it to act up again. We tried for five hours and it started every time. Next morning engine would spin but wouldn't fire. My thought is it has to do with the fuel shut off valve. But what do I know?

Hello,

Can you hear your pump initialize with a "hum". I ran into a problem where a new pump assembly and a relay was installed and a month later it won't start anymore.

Towed to GM Dealer, found out it lost power because a wire harness assembly under the carriage (under driver seat) that takes power to the pump was short. This harness also carries power to other things in rear. A new 8 or 10 port connector was replaced.

My car wouldn't start so finally had it towed. As soon as the mechanic tried it the engine fired and ran fine. Couldn't get it to act up again. We tried for five hours and it started every time. Next morning engine would spin but wouldn't fire. My thought is it has to do with the fuel shut off valve. But what do I know?
Welcome AF. No fuel shutoff valve here. When it won't start you must check for spark and fuel pressure, basic diagnostics.