1997 Grand Prix GT PO300 after 0 degrees

I have a 1997 Pontiac Grand Prix GT and the other day the temperature dropped well below 0 degrees F. The car didn't even seem to want to start. It read a PO300 when i tested it. The engine gets spark and compression and to rule out frozen gas lines i spayed starting fluid in the intake and it still didn't do anything. I replaced the cam sensor and still nothing. I did the lights out test and there are blue sparks jumping in between the plug boots on the coil packs. Any suggestions of what next?

Does it turn over fast or does it seem like the battery is weak. What weight of oil is in it. To thick of oil or old oil can cause hard starting when extreme cold. To slow of cranking can cause engine to get loaded up with fuel. Gm vehicles won't start if cranking voltage falls to low.

Also, when was the last time a tune-up was performed?

Use parts from the dealer...GMs don't like aftermarket parts.