Hi everyone.
The valves on my maxima and the engine, run very loud, rough at cold start. The sound is like a diesel engine or an engine with the timing off. The engine is very "boggy" on the thottle, adding gas makes it worse. It takes around 3 minutes to completely go away. Hot/Warm starts are fine.
What would cause this? Bad gas, some engine sensor??
I recently (4 weeks?) had this car in for an Oxygen sensor repair. Major tuneup was done in December (didn't do it then). It's been getting louder/worse over time. I can live with it, but I'm worried its causing damage to the engine.