Verokosky

Sorry I'm not sure how to use this forum yet.

I have a 2003 350z 6MT
​​180,000KM

I was driving the car just fine all day and as I was on the highway almost home I smelled gas for a brief second, I slowed down for the off ramp and as I started to accelerate again the car started to bog and have trouble accelerating slow or fast. The car runs fine at a constant speed only problems while trying to accelerate. At idle the car constantly back fires and mis fires. I replaced the coil packs and spark plugs 8 months ago. I have spares and tried switching the coil packs out. I also unplugged 1 at a time while the car was running and they all make a difference while unplugged. I had a p0300 code multiple cylinders misfire. While driving sometimes the check engine light will flash. The OBD reader I used said the 02 sensor and catalyst was incomplete.
any recommendations where to start ?
thank you.

SmoothZ

iTrader: (13)

Do you know the maintenance history of the car? If you're running on original cats and injectors, you'll need to consider a healthy maintenance upgrade.

JavanZ33

How bad are your O2 sensors? That may play into it.. I'm searching through forums trying to diagnose a similar issue myself. Just replaced all the coils and spark plugs with brand new oem spec, and still misfiring. Hope that you can get yours figured out..