Gas is getting in my oil in a 350z Nissan. what should I check or could it be my computer telling injectors more gas

Well Anthony without being there to check it myself I will do my best I don't know how long you have owned this car it's 13 years old now they come out the year before or how much mileage is on the motor/ever had overheating problems . o.k. lets go here's the first thing we want to know is mileage this is a pretty good indication of the valve seals condition/combined with if the engine ever overheated this does damage to the seals heat rises and when we are talking about valve seals they are on the top of the head and baking in hot oil all the time when the motor overheats that oil is boiling and the heat is retained like an oven pan by the valve covers so I think you and anybody else reading here get that picture but even with out ever overheating 13 years is a real lot to ask of valve seals although they can last longer than that in cars like this with the racing stuff going on I really don't think so and the gas under compression in the cylinder is escaping through the seals into the valve covers .these engines rev higher than the average daily drivers out there. but that's one possibility the next is worn piston rings the fuel can seep through the ring gaps and eventually into the oil pan. next we have the cheaper of all problems it is possible that your evaporative canister purge valve is not working properly and this is used to return unused fuel into the charcoal canister and then back to the gas tank to be recirculated back to be burned again in combustion if there are vacuum leaks this will affect this system and the e.g.r. exhaust gas recirculation valve this also returns fuel back in to the combustion chamber to be burned but if to much is coming in it can not be burned and on an old motor well you guessed it and last but not forgotten there is a possibility that your fuel pressure regulator is letting way to much fuel in and that will be felt as hesitation because at lower rpm's the motors stumbling trying to burn the excess fuel which can not be removed fast enough and that also will seep through worn rings this is most likely happening in a 2 week time span and the fuel breaks down the oil this will lead to cam/crankshaft bearing failure because the loss of viscosity and the gas is a solvent in oil so it's washing away any protective coating the oil is supposed to leave on the bearings = a dry start up no protection even though they are floating in oil it's broken down oil and has thinned and lost it's slickness DO NOT TRY TO COMPENSATE BY THROWING IN SYNTHETIC OIL IT WILL GO RIGHT BY WORN RINGS AND SEALS AND YOU'LL LOOK LIKE JAMES BOND DRIVING DOWN THE STREET WITH A SMOKE SCREEN BEHIND YOU IF IT'S BEEN IN THERE ALL ALONG THEN THAT IS COMING SOON WHEN I CAN'T SAY SO YOU CAN PUT IN A JUNK YARD MOTOR FOR NOW AND REBUILD YOURS AND HAVE A PERFECT NEWLY REDONE MOTOR FOR THE FUTURE good luck

You did not state which exact model (they vary between countries), you did not state if it is turbo or natural aspirated...

1. head gasket leak
2. if your fuel pump is driven by the engine (mechanical!) then it is possibility that internal seal bearing on the pump is gone hence internal leak.
3. head crack between cylinder/piston space and oil galley above and missing waterline (extremely rare that way!)

these three are most probable causes.

of course burnt/damaged rings, hole in the piston are in that particular model real possibility.

this one is virtually theoretical... injector seat have microline crack and under pressure is pressurising to oil galley.

to check:
1. check your radiator - start engine with removed radiator cup and iddle it for 1 to 2min, accelerate, if bubbles come through - your head gasket is gone and you need to replace it, if this test is negative, you need to check other possibilities.
2. reinstall the radiator cap, remove oil fill cap, put your hand on it and accelerate, if pressure build in - you are in serious money... normal is virtually no pressure just bit of splatter from rockies.

there is no way in which you can check if this is pump seal without proper gauges

this need to be addressed rather urgently, it is more dangerous than water in oil... only drive which you should do should be to closes mechanical workshop...

sorry for being doomsayer... do not forget to vote...

Dump the oil and refill. Take it to a JiffyLube or other oil change depot. Could be that it will not continue. I would take
it to Nissan service if it were my car.