I have a 05 5at with 97XXX km on it. About a couple of months ago I changed the spark plugs and noticed a bit of oil in the back righ plug. I took it in afterword to the dealer and told them I'm pretty sure my valves are leaking. They checked it all out an confirmed that was the case. They ended up changing them under my warrenty. And everything seemed fine. A couple of weeks ago I ended up changing my engine oil. Used some mobil 1 around 4.4 liters changed out the filter with nissans fatory one and everything seemed to be good. Levels were fine no engine light. Drove the car to work a few times everything was good. Today took the car out and I started smelling a weird smell like burning oil. I checked the oil levels again and everything was at the normal levels. So I didn't think much of it I figured maybe I might of had a bit of excess oil from the pour. However later on in the day I notice that the smell and now a smoke comes out of the exhuast after a wot. Under normal driving it seems to be fine but if I open it up a bit I can smell the burn off and I can see the smoke coming from the back end. I have no idea what's happening. Like I stated I drove the car a few times after the inital change with no problem and today all of a sudden this started. I know that if there isn't enough radiator fluid that it might also cause the same problem but the car does not seem like its overheating and the levels were also done when I flushed the rad while installing the new samco hoses. I also recently had seymore (joe) send me a base tune for my uprev flash I have been driving on the performance setting but haven't had any of these issues until today. Any ideas what it can be. I still have a year of extended warrenty but I don't know which way to direct the dealer in.

Thanks in advance.

 

oh the oil that i used was fully synthetic 5-30 mobil one which is the same that i have been using for the last 50xxx km and this is the same one that the dealer uses on their VQs