06 G35x sedan 194k miles, car has a high idle it would idle at 1500-2000rpm, oil smells of gas and just gets thinner. Sparks plugs smell of gas, exhaust is letting white smoke out with the smell of gas. Have done a compression test and changed spark plugs.

I'd do a leakdown just to make sure you aren't dealing with a blown up engine.

What codes is it throwing?

It’s posting a p0300 code

Random misfire code, I'd start with fresh plugs, check for vacuum leaks, thoroughly inspect the coils, see if the code goes away.