Nake350

Thank you for the info. Yes that's what I'm thinking now from doing some more searching online, plus I took some O2 sensor readings today, which show much larger difference between senor 1 and sensor 2 on bank 2. The exhaust sounds really strange too and as it's a cold day, I' not sure if I am imagining it, but there seems less smoke/ vapour coming from the passenger side tail pipe. Think I need a garage.

Just posting incase anyone has had a simiar issue before that can help me diagnose what's happened to my Z. So earler this week I took my 350Z 2007 HR out for a trip to work and just as I got near work (About 10 minute trip) I noticed the exhaust sound got louder. I thought the exhasut was blowing by the sound and the car seemed to have lost some power. It sounded as though it's not running on all cylinders. The oil preasure was still good, but engine warning light came on. I drove it home after work and from the ODB reader I found error code P0300. I was due to change the spark plugs anyway, so did those today, but no improvemnt. The thing is, as the engine warmed up whilst idling, there is a smell of what seems like suphur, which actually got quite strong, so I turned it off. I'm baffled, so any help is much appreciated.