I recently brought home a 99 Camaro with the 3.8L V6, it has been sitting for about 10 years. The fuel pump went bad in it and never got fixed. I took it upon myself to replace it, which was a major pain but I got it done. I cleaned out the tank really good, poured in some Techron fuel additive followed by 5 gallons of non-ethanol. Next, I proceeded to change the fuel filter and removed the quick connects before the engine and cycled the ignition on and off until I got clean fuel. I pulled all the spark plugs, put 15ml of marvel mystery oil into the cylinder, and let it sit overnight. The next morning, I put a socket on the crank and turned it over quite a few times to get all of the excess oil out from the cylinder. I replaced the plugs, got a new battery, and she fired right up. One problem, it's missing pretty bad and threw a PO300. I put a spark plug tester on both sides of the wires and had spark on all 6. I tested the injectors and all were within 12.1-12.3 ohms. Kind of lost and not sure where to go from here, any suggestions are appreciated!