Hi, I own 2 2004 model of audi A4 and i notice a bad smell when i accelerate hard. I had the valve gasket changed, changed the plugs and engine oil, but still smell the bad scent. Can someone pls offer me ideas on what the cause could be?

 

Is the smell in the engine bay or out the tailpipe? if it is the tailpipe try filling up at a different gas station. If it is a burning oil smell check for additional leaks. If the PCV goes bad it can cause oil to blow back. If you haven't replaced that it might be a good idea.

 

what does it smell like?

 

any fluids leaking under the car when parked? possible radiator/coolant leak? my old car had a crack in the radiator and hose and spewed green coolant all over the hot engine and it smoked and smelled bad.