Is this a 5mt or automatic ?
The flashing cruise may be something different.
Don't worry about the full can in the tank, no harm can be done.
Now as for in the oil, you'll want to change the oil very soon, today would be great. These things done like thin oil.
I gather the car has alway's been on the stock MAP. It is known to be flawed and burn valves. That could be the source of the miss fire.
174,000+ miles, 5/20/12 new ej257 short block, 8/20/11 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. Also CHECK YOUR OIL, these cars use it.